diff --git a/.changeset/15178-translation-bundle-split-settings-platform-only.md b/.changeset/15178-translation-bundle-split-settings-platform-only.md
new file mode 100644
index 00000000000..261d92a1429
--- /dev/null
+++ b/.changeset/15178-translation-bundle-split-settings-platform-only.md
@@ -0,0 +1,78 @@
+---
+'@objectstack/spec': minor
+'@objectstack/service-settings': minor
+---
+
+**BREAKING for per-app translation bundles** — the translation bundle type splits in two: `settings` is a PLATFORM group and a per-app bundle may no longer declare it (#15178)
+
+Clause-②: yes
+
+`TranslationDataSchema` served two different bundles at once — the per-app one an
+application authors (`stack.translations`, `defineTranslationBundle`) and the
+code-authored bundles the platform packages ship. It now names the **per-app**
+bundle entry and declares ten groups; the new `PlatformTranslationDataSchema` /
+`PlatformTranslationBundleSchema` (types `PlatformTranslationData` /
+`PlatformTranslationBundle`) carry the eleven-group platform face, `settings`
+included.
+
+### Migration — FROM → TO
+
+| You wrote | Write instead |
+| --- | --- |
+| `defineTranslationBundle({ 'zh-CN': { settings: { mail: { title: '邮件投递' } } } })` | delete the `settings` group — there is no per-app replacement key |
+| `defineStack({ translations: [{ 'zh-CN': { settings: … } }] })` | delete the `settings` group from the bundle entry |
+| `const b: TranslationBundle = { en: { settings: … } }` — a PLATFORM package's own bundle | `const b: PlatformTranslationBundle = { en: { settings: … } }` |
+| `const d: TranslationData = { settings: … }` — a PLATFORM package's own locale entry | `const d: PlatformTranslationData = { settings: … }` |
+
+**The one-line fix for an application: delete the `settings` group.** Settings copy
+is not application-authorable at all — `settings` is keyed by
+`SettingsManifest.namespace` and only platform code declares a manifest, so the
+only namespaces a per-app entry could ever address were the platform's own.
+`settingsCommon` is **not** affected — the Settings UI shell strings (the source
+badges, under `settingsCommon.sourceLabels`) stay on the per-app face; only the
+per-namespace manifest copy under `settings` leaves.
+Run `os migrate meta --from 17` to list the mechanical edits for existing
+sources; apply them by hand.
+
+### What the deletion changes, which is not nothing
+
+⚠️ This is **not** a lossless delete, and the record says so rather than claiming
+the house phrase. Both bundles load into ONE served tree — `AppPlugin`'s
+`loadTranslations` and every platform plugin's `kernel:ready` contribution both
+call `II18nService.loadTranslations`, which deep-merges — and the
+`resolveSettings*` family and the console's settings labels read that merged
+tree. So an app-authored `settings` branch did resolve.
+
+**It was a gap filler, not an override.** The app's bundles are loaded in
+`AppPlugin`'s own `start()` (kernel Phase 2); the platform's settings
+translations arrive from `SettingsServicePlugin`'s `kernel:ready` hook (Phase
+3); `deepMerge` gives the **later** source the leaf. So the platform won every
+key both bundles defined, and a per-app entry rendered **only where the platform
+bundle carried no string for that key and locale** — the platform ships `en`,
+`zh-CN`, `ja-JP` and `es-ES`.
+
+**What to expect after upgrading.** Where the platform already carried the
+string, nothing changes on screen — that value was the one being served all
+along. Where your entry was filling a gap, that Settings screen now renders the
+**manifest's own literal, which is English** (the `?? fallback` every
+`resolveSettings*` helper ends in). Those are the screens to re-read. If a
+platform string is wrong or missing for your locale, correct it in the platform
+bundle (`@objectstack/service-settings`'s `settingsBuiltinTranslations`) — do
+not re-add the app-side copy, which the platform overwrites on every boot
+wherever it has its own value.
+
+No deprecation window: the per-app door refuses the key by name from this major,
+and the rejection carries the prescription above.
+
+### Unchanged
+
+The registered `translation` metadata type (`TranslationItemSchema`) still
+declares `settings` — this ruling covers the file-authored bundle. `GET
+/api/v1/i18n/translations/:locale` still declares it on its response, because the
+served document is the merged tree; `GetTranslationsResponseSchema` is typed
+against the platform face for exactly that reason.
+
+Ruling batch #132 item 2 letter ② (2026-09-13) — 「同意」. The card's original
+"removal" disposition is struck: `settings` is a live platform key.
+
+<!-- adr-0087: registered translation-per-app-settings-removed -->
diff --git a/content/docs/protocol/kernel/i18n-standard.mdx b/content/docs/protocol/kernel/i18n-standard.mdx
index dd0ccf21dc7..0a41d474b91 100644
--- a/content/docs/protocol/kernel/i18n-standard.mdx
+++ b/content/docs/protocol/kernel/i18n-standard.mdx
@@ -398,10 +398,18 @@ Three rules the shape enforces, all of them closed since #4001:
 
 - **The top level is the declared group set and nothing else** — `objects`,
   `apps`, `messages`, `globalActions`, `dashboards`, `datasets`, `pages`,
-  `flows`, `settings`, `metadataForms`, `settingsCommon`. A group invented
-  beside them (`"account"`, `"fields"`, `"list"`, `"industries"`) is rejected
-  **by name** at both authoring doors, with the group to use instead named in
-  the rejection.
+  `flows`, `metadataForms`, `settingsCommon`. A group invented beside them
+  (`"account"`, `"fields"`, `"list"`, `"industries"`) is rejected **by name**
+  at both authoring doors, with the group to use instead named in the
+  rejection.
+- **`settings` is a PLATFORM group and an application bundle may not carry
+  it.** It is keyed by `SettingsManifest.namespace`, and only platform code
+  declares a manifest — so the only namespaces an application could ever
+  address are the platform's own. Writing it in `stack.translations` (or in
+  `defineTranslationBundle`) is refused by name with that prescription; the
+  platform's own bundles author it against `PlatformTranslationData`, and the
+  served document (`GET /i18n/translations/:locale`) carries it because it is
+  the merge of every loaded bundle.
 - **Field options are a map keyed by the option's stored `value`** — never an
   array of `{ value, label }` pairs, and never the display label. See
   [Orphan Keys and Option Keys](#orphan-keys-and-option-keys).
@@ -1046,10 +1054,12 @@ options: { 'Direct Mail': '直邮' }  // ❌ keyed by the label — never resolv
 options: { 'direct-mail': '直邮' }  // ❌ a variant spelling of the value
 ```
 
-`messages`, `settings`, `settingsCommon` and
-`metadataForms` are **not** checked: their keys are owned by application code,
-plugins, and the platform's own metadata-type registry rather than by this
-stack's metadata, so there is no set of legal names to resolve against.
+`messages`, `settingsCommon` and `metadataForms` are **not** checked: their
+keys are owned by application code, plugins, and the platform's own
+metadata-type registry rather than by this stack's metadata, so there is no set
+of legal names to resolve against. (`settings` is not checked either, and since
+it left the per-app bundle it cannot appear in one at all — the parse refuses it
+before any lint runs.)
 
 ### Translation Service Integration
 
diff --git a/content/docs/references/api/protocol.mdx b/content/docs/references/api/protocol.mdx
index 04a73e91547..c89a11f3f05 100644
--- a/content/docs/references/api/protocol.mdx
+++ b/content/docs/references/api/protocol.mdx
@@ -1615,9 +1615,9 @@ The published metadata item body, opaque by ruling (1C). Shape is the item's own
 | **datasets** | `Record<string, { label?: string; description?: string; dimensions?: Record<string, object>; measures?: Record<string, object> }>` | optional | Analytics dataset translations keyed by dataset name |
 | **pages** | `Record<string, { label?: string; description?: string; title?: string; subtitle?: string; … }>` | optional | Page translations keyed by page name |
 | **flows** | `Record<string, { label?: string; screens?: Record<string, object> }>` | optional | Screen-flow translations keyed by flow name |
-| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 | **metadataForms** | `Record<string, { label?: string; description?: string; sections?: Record<string, object>; fields?: Record<string, object> }>` | optional | Translations for metadata-type configuration forms keyed by metadata type |
 | **settingsCommon** | `{ sourceLabels?: object }` | optional | Cross-namespace Settings UI strings |
+| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 
 
 ---
diff --git a/content/docs/references/index.mdx b/content/docs/references/index.mdx
index a2e0ce9dd5c..83f44075f94 100644
--- a/content/docs/references/index.mdx
+++ b/content/docs/references/index.mdx
@@ -1,6 +1,6 @@
 ---
 title: Protocol Reference
-description: Every schema published by @objectstack/spec — 1535 schemas across 14 protocol modules
+description: Every schema published by @objectstack/spec — 1537 schemas across 14 protocol modules
 ---
 
 {/* ⚠️  AUTO-GENERATED — DO NOT EDIT. Run build-docs.ts to regenerate. Hand-written docs live in the module folders under content/docs/. */}
@@ -31,9 +31,9 @@ counts are sums of the rows they head. Regenerate with
 | [Security Protocol](/docs/references/security) | 5 | 30 | Permission sets, row-level security, sharing rules, tenancy posture. |
 | [Shared Protocol](/docs/references/shared) | 10 | 31 | Primitives used across every protocol — identifiers, HTTP, expressions, error maps, enums. |
 | [Studio Protocol](/docs/references/studio) | 3 | 35 | Studio designer metadata — the authoring surfaces for the protocols above. |
-| [System Protocol](/docs/references/system) | 34 | 273 | The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance. |
+| [System Protocol](/docs/references/system) | 34 | 275 | The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance. |
 | [UI Protocol](/docs/references/ui) | 16 | 158 | Apps, pages, views, dashboards, reports, actions and themes — the ObjectUI layer. |
-| **Total** | **195** | **1535** | 14 protocol modules |
+| **Total** | **195** | **1537** | 14 protocol modules |
 
 ---
 
@@ -316,7 +316,7 @@ Studio designer metadata — the authoring surfaces for the protocols above.
 
 ## System Protocol
 
-**Source:** `packages/spec/src/system/` · **Import:** `@objectstack/spec/system` · **34 pages, 273 schemas**
+**Source:** `packages/spec/src/system/` · **Import:** `@objectstack/spec/system` · **34 pages, 275 schemas**
 
 The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance.
 
@@ -354,7 +354,7 @@ The runtime environment — logging, jobs, cache, metrics, notifications, i18n a
 | [`supplier-security.zod.ts`](/docs/references/system/supplier-security) | `SupplierAssessmentStatus`, `SupplierRiskLevel`, `SupplierSecurityAssessment`, `SupplierSecurityPolicy`, `SupplierSecurityRequirement` |
 | [`tenant.zod.ts`](/docs/references/system/tenant) | `DatabaseLevelIsolationStrategy`, `DatabaseProvider`, `QuotaEnforcementResult`, `RowLevelIsolationStrategy`, `SchemaLevelIsolationStrategy`, `Tenant`, `TenantConnectionConfig`, `TenantIsolationConfig`, `TenantIsolationLevel`, `TenantQuota`, `TenantSecurityPolicy`, `TenantUsage` |
 | [`tracing.zod.ts`](/docs/references/system/tracing) | `OpenTelemetryCompatibility`, `OtelExporterType`, `SamplingDecision`, `SamplingStrategyType`, `Span`, `SpanAttributeValue`, `SpanAttributes`, `SpanEvent`, `SpanKind`, `SpanLink`, `SpanStatus`, `TraceContext`, `TraceContextPropagation`, `TraceFlags`, `TracePropagationFormat`, `TraceSamplingConfig`, `TraceState`, `TracingConfig` |
-| [`translation.zod.ts`](/docs/references/system/translation) | `ActionResultDialogTranslation`, `CoverageBreakdownEntry`, `FieldTranslation`, `Locale`, `ObjectTranslationData`, `TranslationBundle`, `TranslationConfig`, `TranslationCoverageResult`, `TranslationData`, `TranslationDiffItem`, `TranslationDiffStatus`, `TranslationItem` |
+| [`translation.zod.ts`](/docs/references/system/translation) | `ActionResultDialogTranslation`, `CoverageBreakdownEntry`, `FieldTranslation`, `Locale`, `ObjectTranslationData`, `PlatformTranslationBundle`, `PlatformTranslationData`, `TranslationBundle`, `TranslationConfig`, `TranslationCoverageResult`, `TranslationData`, `TranslationDiffItem`, `TranslationDiffStatus`, `TranslationItem` |
 | [`worker.zod.ts`](/docs/references/system/worker) | `BatchProgress`, `QueueConfig`, `Task`, `TaskExecutionResult`, `TaskPriority`, `TaskRetryPolicy`, `TaskStatus`, `WorkerStats` |
 
 ---
diff --git a/content/docs/references/system/translation.mdx b/content/docs/references/system/translation.mdx
index d0a74a6331c..7f1755bef65 100644
--- a/content/docs/references/system/translation.mdx
+++ b/content/docs/references/system/translation.mdx
@@ -12,8 +12,8 @@ description: Translation protocol schemas
 ## TypeScript Usage
 
 ```typescript
-import { ActionResultDialogTranslationSchema, CoverageBreakdownEntrySchema, FieldTranslationSchema, LocaleSchema, ObjectTranslationDataSchema, TranslationBundleSchema, TranslationConfigSchema, TranslationCoverageResultSchema, TranslationDataSchema, TranslationDiffItemSchema, TranslationDiffStatusSchema, TranslationItemSchema } from '@objectstack/spec/system';
-import type { ActionResultDialogTranslation, CoverageBreakdownEntry, FieldTranslation, Locale, ObjectTranslationData, TranslationBundle, TranslationConfig, TranslationCoverageResult, TranslationData, TranslationDiffItem, TranslationDiffStatus, TranslationItem } from '@objectstack/spec/system';
+import { ActionResultDialogTranslationSchema, CoverageBreakdownEntrySchema, FieldTranslationSchema, LocaleSchema, ObjectTranslationDataSchema, PlatformTranslationBundleSchema, PlatformTranslationDataSchema, TranslationBundleSchema, TranslationConfigSchema, TranslationCoverageResultSchema, TranslationDataSchema, TranslationDiffItemSchema, TranslationDiffStatusSchema, TranslationItemSchema } from '@objectstack/spec/system';
+import type { ActionResultDialogTranslation, CoverageBreakdownEntry, FieldTranslation, Locale, ObjectTranslationData, PlatformTranslationBundle, PlatformTranslationData, TranslationBundle, TranslationConfig, TranslationCoverageResult, TranslationData, TranslationDiffItem, TranslationDiffStatus, TranslationItem } from '@objectstack/spec/system';
 
 // Validate data
 const result = ActionResultDialogTranslationSchema.parse(data);
@@ -147,11 +147,139 @@ Translation data for a single field
 | **message** | `string` | optional | Translated rejection message — overlays the rule's authored `message` on every rejected write |
 
 
+---
+
+## PlatformTranslationBundle
+
+Map of locale codes to platform translation data
+
+**Type:** `Record<string, { objects?: Record<string, object>; apps?: Record<string, object>; messages?: Record<string, string>; globalActions?: Record<string, object>; … }>`
+
+
+---
+
+## PlatformTranslationData
+
+Platform translation data — the per-app groups plus the platform-only `settings`
+
+### Properties
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **objects** | `Record<string, { label?: string; pluralLabel?: string; description?: string; fields?: Record<string, object>; … }>` | optional | Object translations keyed by object name |
+| **apps** | `Record<string, { label: string; description?: string; navigation?: Record<string, object> }>` | optional | App translations keyed by app name |
+| **messages** | `Record<string, string>` | optional | UI message translations keyed by message ID |
+| **globalActions** | `Record<string, { label?: string; description?: string; confirmText?: string; successMessage?: string; … }>` | optional | Global action translations keyed by action name |
+| **dashboards** | `Record<string, { label?: string; description?: string; actions?: Record<string, object>; widgets?: Record<string, object>; … }>` | optional | Dashboard translations keyed by dashboard name |
+| **datasets** | `Record<string, { label?: string; description?: string; dimensions?: Record<string, object>; measures?: Record<string, object> }>` | optional | Analytics dataset translations keyed by dataset name |
+| **pages** | `Record<string, { label?: string; description?: string; title?: string; subtitle?: string; … }>` | optional | Page translations keyed by page name |
+| **flows** | `Record<string, { label?: string; screens?: Record<string, object> }>` | optional | Screen-flow translations keyed by flow name |
+| **metadataForms** | `Record<string, { label?: string; description?: string; sections?: Record<string, object>; fields?: Record<string, object> }>` | optional | Translations for metadata-type configuration forms keyed by metadata type |
+| **settingsCommon** | `{ sourceLabels?: object }` | optional | Cross-namespace Settings UI strings |
+| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
+
+### Nested Shape: `PlatformTranslationData.objects[string]`
+
+Translation data for a single object
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated singular label |
+| **pluralLabel** | `string` | optional | Translated plural label |
+| **description** | `string` | optional | Translated object description |
+| **fields** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Field-level translations |
+| **_views** | `Record<string, { label?: string; description?: string; emptyState?: object; bulkActions?: Record<string, object> }>` | optional | View translations keyed by view name |
+| **_actions** | `Record<string, { label?: string; description?: string; confirmText?: string; successMessage?: string; … }>` | optional | Action translations keyed by action name |
+| **_sections** | `Record<string, { label?: string; description?: string }>` | optional | Section translations keyed by section name |
+| **_tabs** | `Record<string, { label?: string }>` | optional | Filter-preset tab translations keyed by tab name |
+| **_validations** | `Record<string, { message?: string }>` | optional | Custom validation-rule messages keyed by rule name (`ValidationRuleSchema.name`) |
+
+### Nested Shape: `PlatformTranslationData.apps[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | ✅ | Translated app label |
+| **description** | `string` | optional | Translated app description |
+| **navigation** | `Record<string, { label: string }>` | optional | Navigation group translations keyed by group ID |
+
+### Nested Shape: `PlatformTranslationData.globalActions[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated action label |
+| **description** | `string` | optional | Translated action description — the explanatory line under the title in the action's param dialog |
+| **confirmText** | `string` | optional | Translated confirmation prompt |
+| **successMessage** | `string` | optional | Translated success toast/message |
+| **params** | `Record<string, { label?: string; helpText?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Action parameter translations keyed by parameter name |
+| **resultDialog** | `{ title?: string; description?: string; acknowledge?: string; fields?: Record<string, string> }` | optional | Translations for the action result dialog |
+
+### Nested Shape: `PlatformTranslationData.dashboards[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated dashboard title |
+| **description** | `string` | optional | Translated dashboard description |
+| **actions** | `Record<string, { label?: string }>` | optional | Header action label translations keyed by action url/key |
+| **widgets** | `Record<string, { title?: string; description?: string; subCaption?: string }>` | optional | Widget translations keyed by widget id |
+| **globalFilters** | `Record<string, { label?: string; options?: Record<string, string> }>` | optional | Global-filter translations keyed by the filter `name` (a filter that authors no `name` is keyed by its `field`) |
+
+### Nested Shape: `PlatformTranslationData.datasets[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated dataset label |
+| **description** | `string` | optional | Translated dataset description |
+| **dimensions** | `Record<string, { label?: string }>` | optional | Dimension translations keyed by dimension name (`DatasetDimensionSchema.name`) |
+| **measures** | `Record<string, { label?: string }>` | optional | Measure translations keyed by measure name (`DatasetMeasureSchema.name`) |
+
+### Nested Shape: `PlatformTranslationData.pages[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated page label (nav / breadcrumb) |
+| **description** | `string` | optional | Translated page description |
+| **title** | `string` | optional | Translated `page:header` title (defaults to `label`) |
+| **subtitle** | `string` | optional | Translated `page:header` subtitle |
+| **components** | `Record<string, { title?: string; description?: string; label?: string; placeholder?: string; … }>` | optional | Per-component copy keyed by component id (`PageComponentSchema.id`) |
+
+### Nested Shape: `PlatformTranslationData.flows[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated flow label |
+| **screens** | `Record<string, { title?: string; fields?: Record<string, object> }>` | optional | Screen translations keyed by screen node id (`FlowNode.id`, the client's `ScreenSpec.nodeId`) |
+
+### Nested Shape: `PlatformTranslationData.metadataForms[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **label** | `string` | optional | Translated metadata-type display label (overrides registry label) |
+| **description** | `string` | optional | Translated metadata-type description |
+| **sections** | `Record<string, { label?: string; description?: string }>` | optional | Section translations keyed by section.name |
+| **fields** | `Record<string, { label?: string; helpText?: string; placeholder?: string }>` | optional | Field translations keyed by field path (dot-notation for nested fields) |
+
+### Nested Shape: `PlatformTranslationData.settingsCommon`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **sourceLabels** | `{ env?: string; global?: string; tenant?: string; user?: string; … }` | optional | Source badge labels by resolution layer |
+
+### Nested Shape: `PlatformTranslationData.settings[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **title** | `string` | optional | Translated settings manifest title |
+| **description** | `string` | optional | Translated settings manifest description |
+| **groups** | `Record<string, { title?: string; description?: string }>` | optional | Group translations keyed by group key |
+| **keys** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Per-setting field translations keyed by setting key |
+| **actions** | `Record<string, { label?: string; confirmText?: string; successMessage?: string }>` | optional | Action button translations keyed by action id |
+
+
 ---
 
 ## TranslationBundle
 
-Map of locale codes to translation data
+Map of locale codes to per-app translation data
 
 **Type:** `Record<string, { objects?: Record<string, object>; apps?: Record<string, object>; messages?: Record<string, string>; globalActions?: Record<string, object>; … }>`
 
@@ -222,7 +350,7 @@ Coverage breakdown for a single translation group
 
 ## TranslationData
 
-Translation data for objects, apps, and UI messages
+Per-app translation data for objects, apps, and UI messages
 
 ### Properties
 
@@ -236,7 +364,6 @@ Translation data for objects, apps, and UI messages
 | **datasets** | `Record<string, { label?: string; description?: string; dimensions?: Record<string, object>; measures?: Record<string, object> }>` | optional | Analytics dataset translations keyed by dataset name |
 | **pages** | `Record<string, { label?: string; description?: string; title?: string; subtitle?: string; … }>` | optional | Page translations keyed by page name |
 | **flows** | `Record<string, { label?: string; screens?: Record<string, object> }>` | optional | Screen-flow translations keyed by flow name |
-| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 | **metadataForms** | `Record<string, { label?: string; description?: string; sections?: Record<string, object>; fields?: Record<string, object> }>` | optional | Translations for metadata-type configuration forms keyed by metadata type |
 | **settingsCommon** | `{ sourceLabels?: object }` | optional | Cross-namespace Settings UI strings |
 
@@ -311,16 +438,6 @@ Translation data for a single object
 | **label** | `string` | optional | Translated flow label |
 | **screens** | `Record<string, { title?: string; fields?: Record<string, object> }>` | optional | Screen translations keyed by screen node id (`FlowNode.id`, the client's `ScreenSpec.nodeId`) |
 
-### Nested Shape: `TranslationData.settings[string]`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **title** | `string` | optional | Translated settings manifest title |
-| **description** | `string` | optional | Translated settings manifest description |
-| **groups** | `Record<string, { title?: string; description?: string }>` | optional | Group translations keyed by group key |
-| **keys** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Per-setting field translations keyed by setting key |
-| **actions** | `Record<string, { label?: string; confirmText?: string; successMessage?: string }>` | optional | Action button translations keyed by action id |
-
 ### Nested Shape: `TranslationData.metadataForms[string]`
 
 | Property | Type | Required | Description |
@@ -387,9 +504,9 @@ One locale of translations — the `translation` metadata type
 | **datasets** | `Record<string, { label?: string; description?: string; dimensions?: Record<string, object>; measures?: Record<string, object> }>` | optional | Analytics dataset translations keyed by dataset name |
 | **pages** | `Record<string, { label?: string; description?: string; title?: string; subtitle?: string; … }>` | optional | Page translations keyed by page name |
 | **flows** | `Record<string, { label?: string; screens?: Record<string, object> }>` | optional | Screen-flow translations keyed by flow name |
-| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 | **metadataForms** | `Record<string, { label?: string; description?: string; sections?: Record<string, object>; fields?: Record<string, object> }>` | optional | Translations for metadata-type configuration forms keyed by metadata type |
 | **settingsCommon** | `{ sourceLabels?: object }` | optional | Cross-namespace Settings UI strings |
+| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 | **locale** | `string` | ✅ | BCP-47 locale this item translates (e.g. "zh-CN") |
 | **name** | `string` | optional | Item name — conventionally the locale code (`zh-CN`); the runtime sync falls back to it when `locale` is absent |
 | **label** | `string` | optional | Human-readable label shown in metadata lists |
@@ -472,16 +589,6 @@ Translation data for a single object
 | **label** | `string` | optional | Translated flow label |
 | **screens** | `Record<string, { title?: string; fields?: Record<string, object> }>` | optional | Screen translations keyed by screen node id (`FlowNode.id`, the client's `ScreenSpec.nodeId`) |
 
-### Nested Shape: `TranslationItem.settings[string]`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **title** | `string` | optional | Translated settings manifest title |
-| **description** | `string` | optional | Translated settings manifest description |
-| **groups** | `Record<string, { title?: string; description?: string }>` | optional | Group translations keyed by group key |
-| **keys** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Per-setting field translations keyed by setting key |
-| **actions** | `Record<string, { label?: string; confirmText?: string; successMessage?: string }>` | optional | Action button translations keyed by action id |
-
 ### Nested Shape: `TranslationItem.metadataForms[string]`
 
 | Property | Type | Required | Description |
@@ -497,6 +604,16 @@ Translation data for a single object
 | :--- | :--- | :--- | :--- |
 | **sourceLabels** | `{ env?: string; global?: string; tenant?: string; user?: string; … }` | optional | Source badge labels by resolution layer |
 
+### Nested Shape: `TranslationItem.settings[string]`
+
+| Property | Type | Required | Description |
+| :--- | :--- | :--- | :--- |
+| **title** | `string` | optional | Translated settings manifest title |
+| **description** | `string` | optional | Translated settings manifest description |
+| **groups** | `Record<string, { title?: string; description?: string }>` | optional | Group translations keyed by group key |
+| **keys** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Per-setting field translations keyed by setting key |
+| **actions** | `Record<string, { label?: string; confirmText?: string; successMessage?: string }>` | optional | Action button translations keyed by action id |
+
 
 ---
 
diff --git a/content/docs/ui/translations.mdx b/content/docs/ui/translations.mdx
index 4e16119f3b3..d43d6bf1df0 100644
--- a/content/docs/ui/translations.mdx
+++ b/content/docs/ui/translations.mdx
@@ -80,7 +80,8 @@ export default defineStack({
 | Page labels and `page:header` copy | `pages.<name>.label` / `description` / `title` / `subtitle` — on a `kind: 'slotted'` page the header under `slots.header` is the page's header |
 | Page component copy, by component id | `pages.<name>.components.<id>.title` / `description` / `label` / `placeholder` / `emptyText` — reached under `regions[].components[]` and `slots.<slot>`, through `properties.children` and a `page:tabs` / `page:accordion` panel's `items[].children` |
 | Screen-flow wizards (flow label, screen headings, screen field copy) | `flows.<flow>.label` / `flows.<flow>.screens.<node_id>.title` / `.fields.<field>.label` / `.placeholder` — see the boundary note below |
-| Global actions, settings, messages | `globalActions`, `settings`, `messages` |
+| Global actions, messages | `globalActions`, `messages` |
+| Settings UI shell copy (the source badge on a settings row) | `settingsCommon.sourceLabels.<layer>` — the per-namespace settings copy under `settings` is **platform-only**: an app bundle carrying it is refused by name, and the platform's own strings are translated in `@objectstack/service-settings`'s bundle |
 | A label written as an inline locale map (`label: { en: 'Members', 'zh-CN': '成员' }`) | Nowhere — it is written on the metadata and resolved at render time; see **Current boundaries** below |
 
 The metadata types resolved per request are **object, view, action, app,
@@ -188,7 +189,8 @@ register. Common layouts:
 
 Files are not the only door. A `translation` metadata item — created in the
 Studio, through the metadata API, or by an agent — carries one locale's worth
-of the **same** groups a file bundle uses, plus the `locale` it translates:
+of the **same** groups a file bundle uses, bar the one exception noted below,
+plus the `locale` it translates:
 
 {/* os:check */}
 ```ts
@@ -215,7 +217,11 @@ Two things to know:
   a silent skip is the hardest kind of missing translation to diagnose.
 - Only the groups on this page are accepted, and since #4001 that is literally
   true: a key none of them declares is rejected, in a runtime item **and** in a
-  file-authored bundle. Keys from the retired `o.<object>` shape (`o`, `app`,
+  file-authored bundle. One group differs between the two doors: `settings` is
+  **platform-only** — a file bundle refuses it by name, and although the
+  registered `translation` item still declares it, the only namespaces it can
+  address are the platform's own, because only platform code declares a settings
+  manifest. Keys from the retired `o.<object>` shape (`o`, `app`,
   `nav`, `dashboard`, `_globalOptions`, `_meta`, …) carry a message naming the
   group to use instead — they used to save cleanly and then render nothing
   (#3778). Everything else gets the nearest declared key suggested.
diff --git a/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md b/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
index 195fe7375f9..1e815436dec 100644
--- a/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
+++ b/docs/audits/2026-07-unknown-key-strictness-ledger.counts.md
@@ -264,4 +264,4 @@ directory rather than per file.
 | `marketplace/` | 29 |
 | `qa/` | 6 |
 | `shared/` | 20 |
-| `system/` | 351 |
+| `system/` | 352 |
diff --git a/docs/qa/platform-checklist/areas/i18n.json b/docs/qa/platform-checklist/areas/i18n.json
index 4400ea7f3cd..edcb636e1fd 100644
--- a/docs/qa/platform-checklist/areas/i18n.json
+++ b/docs/qa/platform-checklist/areas/i18n.json
@@ -251,7 +251,7 @@
           "evidence": "the /i18n/locales response"
         },
         {
-          "clause": "GET /i18n/translations/:locale returns a non-empty bundle whose key paths all sit within the declared translation-group vocabulary (translationDataShape) — a key outside the declared groups, or a raw dotted key handed to a consumer, is the silent-strip class",
+          "clause": "GET /i18n/translations/:locale returns a non-empty bundle whose key paths all sit within the declared translation-group vocabulary (PlatformTranslationDataSchema — the SERVED document is the merged tree, so it is the eleven-group platform face and not the ten-group per-app one) — a key outside the declared groups, or a raw dotted key handed to a consumer, is the silent-strip class",
           "oracle": "api",
           "verify": "translations for zh-CN is non-empty; spot-check that sampled keys resolve under objects/_views/_actions/_sections/apps.navigation/dashboards/pages/settings groups, not a fourth dialect",
           "evidence": "the /translations/zh-CN response + the key check"
@@ -299,7 +299,7 @@
       ],
       "traps": ["stale-console-bundle", "hydration-race", "wrong-panel", "dispatcher-vs-hono-route"],
       "source": [
-        "packages/spec/src/system/translation.zod.ts#translationDataShape (translationDataShape — the authoritative group vocabulary: objects/_views/_actions/_sections, apps.navigation, messages, globalActions, dashboards, pages, settings, metadataForms, settingsCommon)",
+        "packages/spec/src/system/translation.zod.ts#appTranslationDataShape (appTranslationDataShape — the group vocabulary an APPLICATION may author: objects/_views/_actions/_sections, apps.navigation, messages, globalActions, dashboards, datasets, pages, flows, metadataForms, settingsCommon. `settings` is platform-only since #15178 and lives in platformSettingsShape, spread into PlatformTranslationDataSchema and TranslationItemSchema)",
         "examples/app-showcase/src/system/translations/index.ts (full-column coverage rationale)",
         "packages/services/service-i18n/src/i18n-service-plugin.ts#i18n (GET /i18n/locales | /translations/:locale | /labels/:object/:locale; { success, data } envelope #3636/#3675; resolveObjectFieldLabels nested shape #3778/#3833; the plugin mount and the dispatcher /i18n domain serve the same routes interchangeably)",
         "packages/services/service-i18n/src/file-i18n-adapter.ts#getLocales (getLocales / getTranslations — unloaded locale → {}; fallbackLocale applies per-KEY in t(), not to the bulk route)",
diff --git a/packages/services/service-settings/src/translations/en.ts b/packages/services/service-settings/src/translations/en.ts
index f4b8d4a1fe8..a9c02d486ce 100644
--- a/packages/services/service-settings/src/translations/en.ts
+++ b/packages/services/service-settings/src/translations/en.ts
@@ -1,6 +1,6 @@
 // Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
 
-import type { TranslationData } from '@objectstack/spec/system';
+import type { PlatformTranslationData } from '@objectstack/spec/system';
 
 /**
  * English (en) — built-in settings manifest translations.
@@ -9,7 +9,7 @@ import type { TranslationData } from '@objectstack/spec/system';
  * Keeping them explicit here lets the resolver chain (locale → fallback → literal)
  * always have at least an English entry to fall back to.
  */
-export const en: TranslationData = {
+export const en: PlatformTranslationData = {
   settingsCommon: {
     sourceLabels: {
       env: 'Env',
diff --git a/packages/services/service-settings/src/translations/es-ES.ts b/packages/services/service-settings/src/translations/es-ES.ts
index 91a04695851..13bab6deb0f 100644
--- a/packages/services/service-settings/src/translations/es-ES.ts
+++ b/packages/services/service-settings/src/translations/es-ES.ts
@@ -1,11 +1,11 @@
 // Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
 
-import type { TranslationData } from '@objectstack/spec/system';
+import type { PlatformTranslationData } from '@objectstack/spec/system';
 
 /**
  * Español (es-ES) — built-in settings manifest translations.
  */
-export const esES: TranslationData = {
+export const esES: PlatformTranslationData = {
   settingsCommon: {
     sourceLabels: {
       env: 'Entorno',
diff --git a/packages/services/service-settings/src/translations/index.ts b/packages/services/service-settings/src/translations/index.ts
index 8f90f32cb5b..433513984b9 100644
--- a/packages/services/service-settings/src/translations/index.ts
+++ b/packages/services/service-settings/src/translations/index.ts
@@ -4,14 +4,15 @@
  * Built-in Settings translations.
  *
  * Mirrors the CRM example's `src/translations/{en,zh-CN,ja-JP}.ts` convention —
- * one file per locale, aggregated into a `TranslationBundle` here.
+ * one file per locale, aggregated into a `PlatformTranslationBundle` here —
+ * the platform face, because `settings` is a platform-only group.
  *
  * Hosts merge `settingsBuiltinTranslations` into the i18next resource tree
  * under whatever namespace makes sense (the console wires it as `system`),
  * making keys resolvable as `<ns>.settings.<namespace>.{title,description,...}`.
  */
 
-import type { TranslationBundle } from '@objectstack/spec/system';
+import type { PlatformTranslationBundle } from '@objectstack/spec/system';
 import { en } from './en.js';
 import { zhCN } from './zh-CN.js';
 import { jaJP } from './ja-JP.js';
@@ -19,7 +20,7 @@ import { esES } from './es-ES.js';
 
 export { en, zhCN, jaJP, esES };
 
-export const settingsBuiltinTranslations: TranslationBundle = {
+export const settingsBuiltinTranslations: PlatformTranslationBundle = {
   en,
   'zh-CN': zhCN,
   'ja-JP': jaJP,
diff --git a/packages/services/service-settings/src/translations/ja-JP.ts b/packages/services/service-settings/src/translations/ja-JP.ts
index 7411c5bc962..2fc44d9b1d8 100644
--- a/packages/services/service-settings/src/translations/ja-JP.ts
+++ b/packages/services/service-settings/src/translations/ja-JP.ts
@@ -1,11 +1,11 @@
 // Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
 
-import type { TranslationData } from '@objectstack/spec/system';
+import type { PlatformTranslationData } from '@objectstack/spec/system';
 
 /**
  * 日本語 (ja-JP) — built-in settings manifest translations.
  */
-export const jaJP: TranslationData = {
+export const jaJP: PlatformTranslationData = {
   settingsCommon: {
     sourceLabels: {
       env: '環境変数',
diff --git a/packages/services/service-settings/src/translations/zh-CN.ts b/packages/services/service-settings/src/translations/zh-CN.ts
index b505112dcef..b79eb708471 100644
--- a/packages/services/service-settings/src/translations/zh-CN.ts
+++ b/packages/services/service-settings/src/translations/zh-CN.ts
@@ -1,11 +1,11 @@
 // Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
 
-import type { TranslationData } from '@objectstack/spec/system';
+import type { PlatformTranslationData } from '@objectstack/spec/system';
 
 /**
  * 简体中文 (zh-CN) — built-in settings manifest translations.
  */
-export const zhCN: TranslationData = {
+export const zhCN: PlatformTranslationData = {
   settingsCommon: {
     sourceLabels: {
       env: '环境变量',
diff --git a/packages/spec/api-surface/system.json b/packages/spec/api-surface/system.json
index c2ff6f40b45..50472f743ce 100644
--- a/packages/spec/api-surface/system.json
+++ b/packages/spec/api-surface/system.json
@@ -500,6 +500,10 @@
     "Plan (type)",
     "PlanParsed (type)",
     "PlanSchema (const)",
+    "PlatformTranslationBundle (type)",
+    "PlatformTranslationBundleSchema (const)",
+    "PlatformTranslationData (type)",
+    "PlatformTranslationDataSchema (const)",
     "PresignedUrlConfig (type)",
     "PresignedUrlConfigSchema (const)",
     "QueueConfig (const)",
diff --git a/packages/spec/authorable-surface/system.json b/packages/spec/authorable-surface/system.json
index 145f12e8707..b3958cde2ec 100644
--- a/packages/spec/authorable-surface/system.json
+++ b/packages/spec/authorable-surface/system.json
@@ -879,6 +879,17 @@
     "system/Plan:limits",
     "system/Plan:priceMonthly",
     "system/Plan:priceYearly",
+    "system/PlatformTranslationData:apps",
+    "system/PlatformTranslationData:dashboards",
+    "system/PlatformTranslationData:datasets",
+    "system/PlatformTranslationData:flows",
+    "system/PlatformTranslationData:globalActions",
+    "system/PlatformTranslationData:messages",
+    "system/PlatformTranslationData:metadataForms",
+    "system/PlatformTranslationData:objects",
+    "system/PlatformTranslationData:pages",
+    "system/PlatformTranslationData:settings",
+    "system/PlatformTranslationData:settingsCommon",
     "system/PresignedUrlConfig:contentType",
     "system/PresignedUrlConfig:expiresIn",
     "system/PresignedUrlConfig:maxSize",
@@ -1276,7 +1287,6 @@
     "system/TranslationData:metadataForms",
     "system/TranslationData:objects",
     "system/TranslationData:pages",
-    "system/TranslationData:settings",
     "system/TranslationData:settingsCommon",
     "system/TranslationDiffItem:aiConfidence",
     "system/TranslationDiffItem:aiSuggested",
diff --git a/packages/spec/declaration-map/system.json b/packages/spec/declaration-map/system.json
index 581a7aa4750..ffd9cdbb2ec 100644
--- a/packages/spec/declaration-map/system.json
+++ b/packages/spec/declaration-map/system.json
@@ -326,6 +326,10 @@
     "PackagePublishResultSchema": "system/PackagePublishResult",
     "Plan": "system/Plan",
     "PlanSchema": "system/Plan",
+    "PlatformTranslationBundle": "system/PlatformTranslationBundle",
+    "PlatformTranslationBundleSchema": "system/PlatformTranslationBundle",
+    "PlatformTranslationData": "system/PlatformTranslationData",
+    "PlatformTranslationDataSchema": "system/PlatformTranslationData",
     "PresignedUrlConfig": "system/PresignedUrlConfig",
     "PresignedUrlConfigSchema": "system/PresignedUrlConfig",
     "QueueConfig": "system/QueueConfig",
diff --git a/packages/spec/export-origins/system.json b/packages/spec/export-origins/system.json
index 4db7a018acf..9c06a6fdd0c 100644
--- a/packages/spec/export-origins/system.json
+++ b/packages/spec/export-origins/system.json
@@ -479,6 +479,10 @@
     "Plan": "src/system/license.zod.ts#Plan (type)",
     "PlanParsed": "src/system/license.zod.ts#PlanParsed (type)",
     "PlanSchema": "src/system/license.zod.ts#PlanSchema (const)",
+    "PlatformTranslationBundle": "src/system/translation.zod.ts#PlatformTranslationBundle (type)",
+    "PlatformTranslationBundleSchema": "src/system/translation.zod.ts#PlatformTranslationBundleSchema (const)",
+    "PlatformTranslationData": "src/system/translation.zod.ts#PlatformTranslationData (type)",
+    "PlatformTranslationDataSchema": "src/system/translation.zod.ts#PlatformTranslationDataSchema (const)",
     "PresignedUrlConfig": "src/system/object-storage.zod.ts#PresignedUrlConfig (type)",
     "PresignedUrlConfigSchema": "src/system/object-storage.zod.ts#PresignedUrlConfigSchema (const)",
     "QueueConfig": "src/system/worker.zod.ts#QueueConfig (type)",
diff --git a/packages/spec/json-schema.manifest/system.json b/packages/spec/json-schema.manifest/system.json
index 1a951e75a20..ad5a1f45f25 100644
--- a/packages/spec/json-schema.manifest/system.json
+++ b/packages/spec/json-schema.manifest/system.json
@@ -178,6 +178,8 @@
     "system/PNCounter",
     "system/PackagePublishResult",
     "system/Plan",
+    "system/PlatformTranslationBundle",
+    "system/PlatformTranslationData",
     "system/PresignedUrlConfig",
     "system/QueueConfig",
     "system/QuotaEnforcementResult",
diff --git a/packages/spec/src/api/protocol.zod.ts b/packages/spec/src/api/protocol.zod.ts
index 5db152247ae..0e78b162a02 100644
--- a/packages/spec/src/api/protocol.zod.ts
+++ b/packages/spec/src/api/protocol.zod.ts
@@ -27,7 +27,7 @@ import {
 import { RealtimePresenceSchema, TransportProtocol } from './realtime.zod';
 import { ObjectPermissionSchema, EffectiveObjectPermissionSchema, FieldPermissionSchema } from '../security/permission.zod';
 import { ActionDescriptorSchema } from '../automation/node-executor.zod';
-import { TranslationDataSchema } from '../system/translation.zod';
+import { PlatformTranslationDataSchema } from '../system/translation.zod';
 // #5950 / #5882 — the ADR-0010 read-side protection envelope both metadata-item
 // responses publish. Same three vocabularies the resolver filters against, so a
 // value this spec cannot name is a value the resolver would have dropped.
@@ -3167,9 +3167,16 @@ export const GetTranslationsRequestSchema = lazySchema(() => z.object({
   locale: z.string().describe('BCP-47 locale code'),
 }));
 
+/**
+ * The served document is the MERGE of every loaded bundle — each platform
+ * package's own contribution at `kernel:ready` plus the app's
+ * `stack.translations` — so it carries the platform-only `settings` group and
+ * is typed against the platform face, not the per-app one
+ * (`system/translation.zod.ts`).
+ */
 export const GetTranslationsResponseSchema = lazySchema(() => z.object({
   locale: z.string().describe('Locale code'),
-  translations: TranslationDataSchema.describe('Translation data'),
+  translations: PlatformTranslationDataSchema.describe('Translation data'),
 }));
 
 export const GetFieldLabelsRequestSchema = lazySchema(() => z.object({
diff --git a/packages/spec/src/conversions/registry.ts b/packages/spec/src/conversions/registry.ts
index 2371b6f4407..562b23f7b16 100644
--- a/packages/spec/src/conversions/registry.ts
+++ b/packages/spec/src/conversions/registry.ts
@@ -7113,6 +7113,105 @@ const elementFormRemoved: MetadataConversion = {
   },
 };
 
+/**
+ * `translation.<locale>.settings` on a PER-APP bundle — the platform-only
+ * group leaving `stack.translations` with the type split (protocol 18,
+ * #15178, ruling batch #132 item 2 letter ②).
+ *
+ * ⛔ NOT a lossless delete, and this entry says so rather than claiming the
+ * house phrase. `settings` is keyed by `SettingsManifest.namespace`, and only
+ * platform code declares a manifest — so the only namespaces an application
+ * could address were the PLATFORM's own. Both bundles are loaded into ONE
+ * served tree (`AppPlugin.loadTranslations` and each platform plugin's
+ * `kernel:ready` contribution both call `II18nService.loadTranslations`, which
+ * deep-merges), and `resolveSettingsTitle` / the console's `useSettingsLabel`
+ * read that merged tree, so an app-authored entry DID resolve.
+ *
+ * What it did NOT do is override the platform. `AppPlugin` loads the app's
+ * bundles in its own `start()` (kernel Phase 2); `SettingsServicePlugin`
+ * contributes the platform's settings translations from a `kernel:ready` hook
+ * (Phase 3); `deepMerge` gives the LATER source the leaf. So the platform won
+ * every key both bundles defined, and a per-app entry rendered only where the
+ * platform bundle carried no string for that key and locale — a gap filler on
+ * a namespace the application does not own. Dropping it therefore takes those
+ * gaps back to the manifest's own literal (the `?? fallback` every
+ * `resolveSettings*` helper ends in), which is a VISIBLE change and not a
+ * no-op. The semantic entry
+ * `18.translation-per-app-settings-platform-only.ts` is where an author is
+ * told that, because a notice reading "(removed)" does not say it.
+ *
+ * ⚠️ The BUNDLE shape only. `TranslationItemSchema` still declares `settings`
+ * (the registered `translation` metadata type is out of this ruling's scope),
+ * so a bare item entry replaying through this seam is left exactly as it is —
+ * the opposite of the `translation-component-submit-label-removed` neighbour,
+ * which retires its key at both doors and therefore walks both shapes. Getting
+ * this backwards would strip a key its own schema still accepts.
+ *
+ * The bundle is told from an item structurally rather than by key spelling:
+ * `locale` is REQUIRED on an item and never present on a bundle entry (the
+ * bundle's keys ARE the locales), and the candidate value must be a dict whose
+ * every key is a declared translation group — which an `objects` record, the
+ * one other dict-of-dicts at that depth, is not.
+ */
+const translationPerAppSettingsRemoved: MetadataConversion = {
+  id: 'translation-per-app-settings-removed',
+  toMajor: 18,
+  retiredFromLoadPath: true,
+  surface: 'stack.translations[].<locale>.settings',
+  summary:
+    "per-app translation group 'settings' removed (#15178 — it is keyed by SettingsManifest.namespace "
+    + 'and only platform code declares a manifest, so an app-authored entry could only fill gaps the '
+    + "platform's own bundle left in the one merged served tree, and was overwritten wherever both "
+    + 'defined the key; those gaps now fall back to the manifest literal, and the group stays on the '
+    + 'PLATFORM bundle, PlatformTranslationData)',
+  apply(stack, emit) {
+    /** The top-level groups a translation bundle entry may carry (either face). */
+    const GROUPS = new Set([
+      'objects', 'apps', 'messages', 'globalActions', 'dashboards', 'datasets',
+      'pages', 'flows', 'settings', 'metadataForms', 'settingsCommon',
+    ]);
+    return mapCollection(stack, 'translations', (entry, path) => {
+      // A `translation` ITEM, not a bundle — `settings` is still declared
+      // there. Leave it whole.
+      if ('locale' in entry) return entry;
+      let next = entry;
+      for (const [locale, data] of Object.entries(entry)) {
+        if (!isDict(data) || !isDict(data.settings)) continue;
+        if (!Object.keys(data).every((k) => GROUPS.has(k))) continue;
+        const stripped = stripKeys(data, ['settings'], emit, `${path}.${locale}`);
+        if (stripped === data) continue;
+        next = next === entry ? { ...entry } : next;
+        next[locale] = stripped;
+      }
+      return next;
+    });
+  },
+  fixture: {
+    before: {
+      translations: [
+        {
+          'zh-CN': {
+            settings: { mail: { title: '邮件投递', keys: { host: { label: '主机' } } } },
+            // A neighbouring group on the same entry rides through untouched.
+            apps: { crm: { label: '客户关系管理' } },
+          },
+        },
+      ],
+    },
+    after: {
+      translations: [
+        {
+          'zh-CN': {
+            apps: { crm: { label: '客户关系管理' } },
+          },
+        },
+      ],
+    },
+    // One per stripped group: the single `zh-CN` entry.
+    expectedNotices: 1,
+  },
+};
+
 /**
  * `translation.pages.<name>.components.<id>.submitLabel` — the component-copy
  * key retired with its only declarer (protocol 18, #10926, ADR-0049).
@@ -10060,6 +10159,7 @@ export const CONVERSIONS_BY_MAJOR: Readonly<Record<number, readonly MetadataConv
     pageAssignedProfilesRemoved,
     chartConfigAriaRemoved,
     dashboardWidgetChartConfigStructureRemoved,
+    translationPerAppSettingsRemoved,
   ],
 };
 
diff --git a/packages/spec/src/migrations/entries/semantic/18.translation-per-app-settings-platform-only.ts b/packages/spec/src/migrations/entries/semantic/18.translation-per-app-settings-platform-only.ts
new file mode 100644
index 00000000000..2f19d4948ea
--- /dev/null
+++ b/packages/spec/src/migrations/entries/semantic/18.translation-per-app-settings-platform-only.ts
@@ -0,0 +1,83 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+import { TranslationDataSchema } from '../../../system/translation.zod.js';
+import type { SemanticMigration } from '../../types.js';
+
+// The judgment half of `translation-per-app-settings-removed`. The D2
+// conversion deletes the group mechanically; what it cannot say in a
+// `to: '(removed)'` notice is WHERE those strings were rendering — only in the
+// gaps the platform's own bundle left — and that deleting them sends those
+// gaps back to the manifest's English literal.
+export const entry: SemanticMigration = {
+  id: 'translation-per-app-settings-platform-only',
+  surface: 'stack.translations[].<locale>.settings — the per-app bundle’s settings group',
+  // The group names are DERIVED from `TranslationDataSchema.shape`, never typed
+  // out beside it. A hand-maintained copy of a schema's key set is the construct
+  // that drifted to nine-of-ten in this very message, so the copy is deleted
+  // rather than pinned: there is one spelling of the set, and a group added to
+  // the per-app face reaches this sentence the day it is declared.
+  // `Object.keys` on a zod object shape yields the declaration order of the
+  // literal it was built from — the order this sentence promises the operator.
+  // A getter, not an eager template: importing the registry must not force the
+  // lazy translation schema at module load.
+  get replacement(): string {
+    const groups = Object.keys(TranslationDataSchema.shape);
+    return 'Delete the group from the per-app bundle. There is no per-app replacement key: settings copy '
+      + 'is not application-authorable at all. `settings` is keyed by `SettingsManifest.namespace`, '
+      + 'and only platform code declares a manifest '
+      + '(`packages/services/service-settings/src/manifests/*.manifest.ts`), so the only namespaces a '
+      + 'per-app entry could ever address were the platform’s own. Platform settings copy is '
+      + 'translated in the PLATFORM bundle — `@objectstack/service-settings`’s '
+      + '`settingsBuiltinTranslations`, typed `PlatformTranslationData` — which is where a correction '
+      + 'to a platform string belongs. An application’s own copy goes in the '
+      + `${groups.length} groups the per-app bundle still declares, in the order it declares them: `
+      + groups.map((g) => `\`${g}\``).join(', ')
+      + '. Note `settingsCommon` among them: it IS on this face, so the Settings UI shell strings an '
+      + 'application may translate (the source badges, under `settingsCommon.sourceLabels`) are NOT '
+      + 'what is being removed here — only the per-namespace manifest copy under `settings` is.';
+  },
+  reason:
+    'Not losslessly convertible, and NOT because the content was inert — but not because it '
+    + 'overrode anything either. Measured on this tree before the split: '
+    + '`AppPlugin.loadTranslations` hands each `stack.translations` bundle entry WHOLE to '
+    + '`II18nService.loadTranslations`, the adapter deep-merges it into the one per-locale tree, and '
+    + 'every platform plugin contributes into that same tree — so `settings` from an app bundle and '
+    + '`settings` from `@objectstack/service-settings` land in one place. `resolveSettingsTitle` and '
+    + 'the rest of the `resolveSettings*` family read it (`pickSettingsEntry` → '
+    + "`pickData(bundle, locale)?.settings`), and so does the console's `useSettingsLabel`, which "
+    + 'scans every namespace carrying a `settings` branch; the liveness ledger '
+    + '`packages/spec/liveness/translation.json` records that reader with its evidence pointer. '
+    + 'ORDER decides the rest, and it runs against the application: `AppPlugin` loads the app’s '
+    + 'bundles in its own `start()` (kernel Phase 2), `SettingsServicePlugin` contributes the '
+    + 'platform’s settings translations from a `kernel:ready` hook (Phase 3), and `deepMerge` gives '
+    + 'the LATER source the leaf — `AppPlugin`’s own comment says as much (“the platform bundles have '
+    + 'not arrived yet at this point in the lifecycle”). So the platform won every key both bundles '
+    + 'defined, and what an application actually had was a GAP FILLER on a namespace it does not own: '
+    + 'the entry rendered only where the platform bundle carried no string for that key and locale '
+    + '(the platform ships en / zh-CN / ja-JP / es-ES), silently, with no way for the author to tell '
+    + 'a filled gap from an ignored override. Dropping the group therefore takes those gaps back to '
+    + 'the manifest’s own literal — the `?? fallback` every `resolveSettings*` helper ends in, which '
+    + 'is English — and that is a VISIBLE change to what a Settings screen renders, not a no-op, '
+    + 'which a mechanical notice reading "(removed)" does not convey. The two bundles are separate '
+    + 'namespaces from this major on (ruling batch #132 item 2 letter ②, 2026-09-13; ADR-0049 '
+    + 'enforce-or-remove supplied the question, not the answer — the maintainer struck the card’s own '
+    + 'removal disposition, because `settings` is a LIVE platform key). No deprecation window: the '
+    + 'per-app door refuses the key by name from this major, with the prescription on the rejection.',
+  acceptanceCriteria:
+    'No per-app bundle carries `settings`: `defineTranslationBundle({ <locale>: { settings: … } })` '
+    + 'and a `defineStack({ translations: [...] })` entry carrying it are both refused as an '
+    + 'unrecognized key, and the refusal names the group as platform-only rather than suggesting a '
+    + 'rename (pinned in `packages/spec/src/system/translation.test.ts`). The platform face still '
+    + 'accepts it: `PlatformTranslationDataSchema.parse({ settings: … })` succeeds, '
+    + '`settingsBuiltinTranslations` still type-checks, and `GET /api/v1/i18n/translations/:locale` '
+    + 'still declares `settings` on its response (`GetTranslationsResponseSchema`), because the '
+    + 'served document is the merged tree. The registered `translation` metadata type is unchanged '
+    + 'and still declares `settings`. For a deployment that WAS authoring per-app settings copy: the '
+    + 'screens to re-read after the upgrade are the ones where it was FILLING A GAP — a namespace, '
+    + 'key or locale the platform bundle does not translate — because those now render the '
+    + 'manifest’s own literal, which is English. Everywhere the platform already carried the string, '
+    + 'nothing changes on screen: the platform value was already the one being served. If a platform '
+    + 'string is wrong or missing for your locale, correct it in the platform bundle '
+    + '(`@objectstack/service-settings`’s `settingsBuiltinTranslations`) — ⛔ do not re-add the '
+    + 'app-side copy, which the platform overwrites on every boot wherever it has its own value.',
+};
diff --git a/packages/spec/src/migrations/registry.ts b/packages/spec/src/migrations/registry.ts
index 213a29821f6..f6c5ee6c3c2 100644
--- a/packages/spec/src/migrations/registry.ts
+++ b/packages/spec/src/migrations/registry.ts
@@ -38,6 +38,13 @@
  * hand-written and still merges as text.
  */
 
+// A VALUE import, and the only one here: an entry literal below derives its
+// group enumeration from this schema's own keys rather than restating them
+// (`translation-per-app-settings-platform-only`). Entry files carry their own
+// copy of this import, but the generator treats a file's imports as scaffolding
+// and concatenates only the literal — so an entry that references a value needs
+// that value in scope HERE, hand-written, outside the generated regions.
+import { TranslationDataSchema } from '../system/translation.zod.js';
 import type { MigrationStep } from './types.js';
 
 /**
@@ -5211,7 +5218,20 @@ const step18: MigrationStep = {
     + 'dashboard widgets only — `ReportChartSchema` and the inline-data react `<ObjectChart>` '
     + 'tier keep their own axes — and the paired semantic entry carries what the stripped '
     + 'keys were saying, because an authored axis field may name a column the widget never '
-    + 'selected and no walker can move that intent into the dataset.',
+    + 'selected and no walker can move that intent into the dataset. '
+    + 'Finally, it splits the translation bundle type in two (#15178, ruling batch #132 item 2 '
+    + 'letter ②): the platform bundle keeps all eleven groups and the per-app bundle '
+    + '(`stack.translations`, `defineTranslationBundle`) no longer declares `settings`, which is '
+    + 'keyed by `SettingsManifest.namespace` and only platform code declares a manifest. Both '
+    + 'bundles load into ONE served tree, so an app-authored `settings` branch did not sit inert — '
+    + 'but nor did it override the platform: the app’s bundles arrive in `AppPlugin`’s `start()` '
+    + '(Phase 2) and the platform’s at `kernel:ready` (Phase 3), and `deepMerge` gives the later '
+    + 'source the leaf, so what an application had was a GAP FILLER on a namespace it does not own '
+    + '— rendering only where the platform bundle carried no string for that key and locale. The '
+    + 'D2 conversion strips the group from per-app bundle entries only (never from a `translation` '
+    + 'ITEM, which still declares it), and the paired semantic entry says what the strip means, '
+    + 'because a notice reading "(removed)" does not say that those gaps fall back to the '
+    + "manifest's own English literal.",
   conversionIds: [
     'field-malformed-scale-precision-removed',
     'record-chatter-position-vocabulary',
@@ -5244,6 +5264,7 @@ const step18: MigrationStep = {
     'page-assigned-profiles-removed',
     'chart-config-aria-removed',
     'dashboard-widget-chart-config-structure-removed',
+    'translation-per-app-settings-removed',
   ],
   semantic: [
     // One file per entry under `entries/semantic/`, concatenated here sorted by
@@ -12410,6 +12431,84 @@ const step18: MigrationStep = {
         + 'and must be verified as such: nothing ever parsed or read these shapes, so removing '
         + 'them removes no behaviour.',
     },
+    // The judgment half of `translation-per-app-settings-removed`. The D2
+    // conversion deletes the group mechanically; what it cannot say in a
+    // `to: '(removed)'` notice is WHERE those strings were rendering — only in the
+    // gaps the platform's own bundle left — and that deleting them sends those
+    // gaps back to the manifest's English literal.
+    {
+      id: 'translation-per-app-settings-platform-only',
+      surface: 'stack.translations[].<locale>.settings — the per-app bundle’s settings group',
+      // The group names are DERIVED from `TranslationDataSchema.shape`, never typed
+      // out beside it. A hand-maintained copy of a schema's key set is the construct
+      // that drifted to nine-of-ten in this very message, so the copy is deleted
+      // rather than pinned: there is one spelling of the set, and a group added to
+      // the per-app face reaches this sentence the day it is declared.
+      // `Object.keys` on a zod object shape yields the declaration order of the
+      // literal it was built from — the order this sentence promises the operator.
+      // A getter, not an eager template: importing the registry must not force the
+      // lazy translation schema at module load.
+      get replacement(): string {
+        const groups = Object.keys(TranslationDataSchema.shape);
+        return 'Delete the group from the per-app bundle. There is no per-app replacement key: settings copy '
+          + 'is not application-authorable at all. `settings` is keyed by `SettingsManifest.namespace`, '
+          + 'and only platform code declares a manifest '
+          + '(`packages/services/service-settings/src/manifests/*.manifest.ts`), so the only namespaces a '
+          + 'per-app entry could ever address were the platform’s own. Platform settings copy is '
+          + 'translated in the PLATFORM bundle — `@objectstack/service-settings`’s '
+          + '`settingsBuiltinTranslations`, typed `PlatformTranslationData` — which is where a correction '
+          + 'to a platform string belongs. An application’s own copy goes in the '
+          + `${groups.length} groups the per-app bundle still declares, in the order it declares them: `
+          + groups.map((g) => `\`${g}\``).join(', ')
+          + '. Note `settingsCommon` among them: it IS on this face, so the Settings UI shell strings an '
+          + 'application may translate (the source badges, under `settingsCommon.sourceLabels`) are NOT '
+          + 'what is being removed here — only the per-namespace manifest copy under `settings` is.';
+      },
+      reason:
+        'Not losslessly convertible, and NOT because the content was inert — but not because it '
+        + 'overrode anything either. Measured on this tree before the split: '
+        + '`AppPlugin.loadTranslations` hands each `stack.translations` bundle entry WHOLE to '
+        + '`II18nService.loadTranslations`, the adapter deep-merges it into the one per-locale tree, and '
+        + 'every platform plugin contributes into that same tree — so `settings` from an app bundle and '
+        + '`settings` from `@objectstack/service-settings` land in one place. `resolveSettingsTitle` and '
+        + 'the rest of the `resolveSettings*` family read it (`pickSettingsEntry` → '
+        + "`pickData(bundle, locale)?.settings`), and so does the console's `useSettingsLabel`, which "
+        + 'scans every namespace carrying a `settings` branch; the liveness ledger '
+        + '`packages/spec/liveness/translation.json` records that reader with its evidence pointer. '
+        + 'ORDER decides the rest, and it runs against the application: `AppPlugin` loads the app’s '
+        + 'bundles in its own `start()` (kernel Phase 2), `SettingsServicePlugin` contributes the '
+        + 'platform’s settings translations from a `kernel:ready` hook (Phase 3), and `deepMerge` gives '
+        + 'the LATER source the leaf — `AppPlugin`’s own comment says as much (“the platform bundles have '
+        + 'not arrived yet at this point in the lifecycle”). So the platform won every key both bundles '
+        + 'defined, and what an application actually had was a GAP FILLER on a namespace it does not own: '
+        + 'the entry rendered only where the platform bundle carried no string for that key and locale '
+        + '(the platform ships en / zh-CN / ja-JP / es-ES), silently, with no way for the author to tell '
+        + 'a filled gap from an ignored override. Dropping the group therefore takes those gaps back to '
+        + 'the manifest’s own literal — the `?? fallback` every `resolveSettings*` helper ends in, which '
+        + 'is English — and that is a VISIBLE change to what a Settings screen renders, not a no-op, '
+        + 'which a mechanical notice reading "(removed)" does not convey. The two bundles are separate '
+        + 'namespaces from this major on (ruling batch #132 item 2 letter ②, 2026-09-13; ADR-0049 '
+        + 'enforce-or-remove supplied the question, not the answer — the maintainer struck the card’s own '
+        + 'removal disposition, because `settings` is a LIVE platform key). No deprecation window: the '
+        + 'per-app door refuses the key by name from this major, with the prescription on the rejection.',
+      acceptanceCriteria:
+        'No per-app bundle carries `settings`: `defineTranslationBundle({ <locale>: { settings: … } })` '
+        + 'and a `defineStack({ translations: [...] })` entry carrying it are both refused as an '
+        + 'unrecognized key, and the refusal names the group as platform-only rather than suggesting a '
+        + 'rename (pinned in `packages/spec/src/system/translation.test.ts`). The platform face still '
+        + 'accepts it: `PlatformTranslationDataSchema.parse({ settings: … })` succeeds, '
+        + '`settingsBuiltinTranslations` still type-checks, and `GET /api/v1/i18n/translations/:locale` '
+        + 'still declares `settings` on its response (`GetTranslationsResponseSchema`), because the '
+        + 'served document is the merged tree. The registered `translation` metadata type is unchanged '
+        + 'and still declares `settings`. For a deployment that WAS authoring per-app settings copy: the '
+        + 'screens to re-read after the upgrade are the ones where it was FILLING A GAP — a namespace, '
+        + 'key or locale the platform bundle does not translate — because those now render the '
+        + 'manifest’s own literal, which is English. Everywhere the platform already carried the string, '
+        + 'nothing changes on screen: the platform value was already the one being served. If a platform '
+        + 'string is wrong or missing for your locale, correct it in the platform bundle '
+        + '(`@objectstack/service-settings`’s `settingsBuiltinTranslations`) — ⛔ do not re-add the '
+        + 'app-side copy, which the platform overwrites on every boot wherever it has its own value.',
+    },
     {
       id: 'ui-action-undoable-unfulfillable-refused',
       surface: '`action` documents declaring `undoable: true` on a shape no runtime fulfils — '
diff --git a/packages/spec/src/system/i18n-resolver.ts b/packages/spec/src/system/i18n-resolver.ts
index 39d432d69fc..755544466a0 100644
--- a/packages/spec/src/system/i18n-resolver.ts
+++ b/packages/spec/src/system/i18n-resolver.ts
@@ -57,7 +57,11 @@
 
 import { mapFlowNodeList } from '../conversions/walk.js';
 
-import type { TranslationBundle, TranslationData } from './translation.zod';
+import type {
+  PlatformTranslationBundle,
+  TranslationBundle,
+  TranslationData,
+} from './translation.zod';
 
 /**
  * Minimal view shape consumed by `resolveViewLabel`.
@@ -310,10 +314,10 @@ export function resolveBundleLocale(
   return undefined;
 }
 
-function pickData(
-  bundle: TranslationBundle | undefined,
+function pickData<D>(
+  bundle: Record<string, D> | undefined,
   locale: string,
-): TranslationData | undefined {
+): D | undefined {
   if (!bundle) return undefined;
   const exact = bundle[locale];
   if (exact !== undefined) return exact;
@@ -2664,7 +2668,7 @@ export function translateObject<T extends ObjectLike>(
 // ────────────────────────────────────────────────────────────────────────────
 
 function pickSettingsEntry(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   locale: string,
 ) {
@@ -2672,7 +2676,7 @@ function pickSettingsEntry(
 }
 
 function resolveOptionalString(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   pick: (entry: NonNullable<ReturnType<typeof pickSettingsEntry>>) => string | undefined,
   opts?: ResolveOptions,
@@ -2689,7 +2693,7 @@ function resolveOptionalString(
 
 /** Resolve manifest title; falls back to literal. */
 export function resolveSettingsTitle(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   fallback: string,
   opts?: ResolveOptions,
@@ -2699,7 +2703,7 @@ export function resolveSettingsTitle(
 
 /** Resolve manifest description. Returns literal (possibly undefined) when no translation found. */
 export function resolveSettingsDescription(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   fallback: string | undefined,
   opts?: ResolveOptions,
@@ -2709,7 +2713,7 @@ export function resolveSettingsDescription(
 
 /** Resolve a group title under `settings.<namespace>.groups.<group>.title`. */
 export function resolveSettingsGroupTitle(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   groupKey: string,
   fallback: string,
@@ -2722,7 +2726,7 @@ export function resolveSettingsGroupTitle(
 }
 
 export function resolveSettingsGroupDescription(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   groupKey: string,
   fallback: string | undefined,
@@ -2736,7 +2740,7 @@ export function resolveSettingsGroupDescription(
 
 /** Resolve a setting field label under `settings.<namespace>.keys.<key>.label`. */
 export function resolveSettingsFieldLabel(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   key: string,
   fallback: string,
@@ -2748,7 +2752,7 @@ export function resolveSettingsFieldLabel(
 }
 
 export function resolveSettingsFieldHelp(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   key: string,
   fallback: string | undefined,
@@ -2760,7 +2764,7 @@ export function resolveSettingsFieldHelp(
 }
 
 export function resolveSettingsFieldPlaceholder(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   key: string,
   fallback: string | undefined,
@@ -2774,7 +2778,7 @@ export function resolveSettingsFieldPlaceholder(
 
 /** Resolve an enum option label under `settings.<namespace>.keys.<key>.options.<value>`. */
 export function resolveSettingsOptionLabel(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   key: string,
   optionValue: string,
@@ -2793,7 +2797,7 @@ export function resolveSettingsOptionLabel(
 
 /** Resolve an action button label under `settings.<namespace>.actions.<actionId>.label`. */
 export function resolveSettingsActionLabel(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   actionId: string,
   fallback: string,
@@ -2806,7 +2810,7 @@ export function resolveSettingsActionLabel(
 }
 
 export function resolveSettingsActionConfirm(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   actionId: string,
   fallback: string | undefined,
@@ -2819,7 +2823,7 @@ export function resolveSettingsActionConfirm(
 }
 
 export function resolveSettingsActionSuccess(
-  bundle: TranslationBundle | undefined,
+  bundle: PlatformTranslationBundle | undefined,
   namespace: string,
   actionId: string,
   fallback: string | undefined,
diff --git a/packages/spec/src/system/translation.test.ts b/packages/spec/src/system/translation.test.ts
index f64a71d993a..dd6baecda7e 100644
--- a/packages/spec/src/system/translation.test.ts
+++ b/packages/spec/src/system/translation.test.ts
@@ -6,6 +6,9 @@ import { ScreenConfigSchema, ScreenFieldConfigSchema } from '../automation/built
 import {
   TranslationDataSchema,
   TranslationBundleSchema,
+  PlatformTranslationDataSchema,
+  PlatformTranslationBundleSchema,
+  defineTranslationBundle,
   LocaleSchema,
   FieldTranslationSchema,
   ObjectTranslationDataSchema,
@@ -786,7 +789,6 @@ describe('translation unknown-key strictness (#4001)', () => {
     ['a page translation', { pages: { home: { subtitel: 'Welcome' } } }, 'subtitle'],
     ['a dashboard widget', { dashboards: { sales: { widgets: { rev: { titel: 'Revenue' } } } } }, 'title'],
     ['a dashboard global filter', { dashboards: { sales: { globalFilters: { region: { lable: 'Region' } } } } }, 'label'],
-    ['a settings key', { settings: { mail: { keys: { host: { lable: 'Host' } } } } }, 'label'],
     ['a metadata form field', { metadataForms: { object: { fields: { name: { helpTxt: 'x' } } } } }, 'helpText'],
   ])('rejects a typo in %s and names the key it meant', (_what, body, expected) => {
     const result = TranslationDataSchema.safeParse(body);
@@ -795,6 +797,19 @@ describe('translation unknown-key strictness (#4001)', () => {
       .toContain(`→ \`${expected}\``);
   });
 
+  it.each([
+    ['a settings key', { settings: { mail: { keys: { host: { lable: 'Host' } } } } }, 'label'],
+  ])('rejects a typo in %s on the PLATFORM face and names the key it meant', (_what, body, expected) => {
+    // Same probe as the per-app battery above, moved rather than deleted: the
+    // group left the per-app door with #15178, so the per-app schema answers
+    // `settings` itself now (the battery two blocks down) and the nested-key
+    // suggester can only be exercised where the group still exists.
+    const result = PlatformTranslationDataSchema.safeParse(body);
+    expect(result.success).toBe(false);
+    expect(result.error?.issues.find((i) => i.code === 'unrecognized_keys')?.message)
+      .toContain(`\u2192 \`${expected}\``);
+  });
+
   it.each([
     ['object', { objects: { account: { views: {} } } }, '_views'],
     ['object', { objects: { account: { actions: {} } } }, '_actions'],
@@ -1259,8 +1274,10 @@ describe('translation unknown-key strictness (#4001)', () => {
   });
 
   it('still accepts every declared group together', () => {
-    // The shape is spread into two schemas (bundle entry + metadata item); this
-    // is the guard against closing one of them against a stale key list.
+    // The shape is spread into three schemas (per-app bundle entry, platform
+    // bundle entry, metadata item); this is the guard against closing one of
+    // them against a stale key list. `settings` is the one group the per-app
+    // face does NOT take, so it is authored separately below.
     const body = {
       objects: { account: { label: 'Account', _views: { all: { label: 'All', emptyState: { title: 'None' } } } } },
       apps: { crm: { label: 'CRM', navigation: { sales: { label: 'Sales' } } } },
@@ -1269,12 +1286,56 @@ describe('translation unknown-key strictness (#4001)', () => {
       dashboards: { sales: { label: 'Sales', widgets: { rev: { title: 'Revenue', subCaption: 'vs last quarter' } }, globalFilters: { region: { label: 'Region', options: { emea: 'EMEA' } } } } },
       pages: { home: { label: 'Home', title: 'Welcome' } },
       flows: { lead_conversion: { label: 'Convert Lead', screens: { details: { title: 'Details', fields: { name: { label: 'Name', placeholder: 'Enter a name' } } } } } },
-      settings: { mail: { title: 'Mail', keys: { host: { label: 'Host' } } } },
       metadataForms: { object: { label: 'Object', fields: { name: { label: 'Name' } } } },
       settingsCommon: { sourceLabels: { env: 'Env', tenant: 'Tenant' } },
     };
+    const settings = { mail: { title: 'Mail', keys: { host: { label: 'Host' } } } };
     expect(() => TranslationDataSchema.parse(body)).not.toThrow();
-    expect(() => TranslationItemSchema.parse({ locale: 'en', ...body })).not.toThrow();
+    expect(() => PlatformTranslationDataSchema.parse({ ...body, settings })).not.toThrow();
+    expect(() => TranslationItemSchema.parse({ locale: 'en', ...body, settings })).not.toThrow();
+  });
+
+  // ──────────────────────────────────────────────────────────────────────────
+  // #15178 — `settings` is a PLATFORM group; the per-app door refuses it
+  // ──────────────────────────────────────────────────────────────────────────
+  describe('per-app `settings` is refused with the platform-only prescription (#15178)', () => {
+    const settings = { mail: { title: 'Mail', keys: { host: { label: 'Host' } } } };
+
+    it.each([
+      ['`settings`', 'settings'],
+      // The singular used to be an ALIAS for `settings`; an alias whose target
+      // the shape no longer accepts is a suggestion the author cannot take, so
+      // it rides the same prescription instead.
+      ['the singular `setting`', 'setting'],
+    ])('refuses %s on a per-app bundle entry', (_what, key) => {
+      const result = TranslationDataSchema.safeParse({ [key]: settings });
+      expect(result.success).toBe(false);
+      const message = result.error?.issues.find((i) => i.code === 'unrecognized_keys')?.message ?? '';
+      // The prescription, not a rename: naming a key this door rejects would
+      // send the author into a second rejection.
+      expect(message).toContain('PLATFORM group');
+      expect(message).toContain('PlatformTranslationData');
+      expect(message).not.toContain(`\`${key}\` \u2192`);
+    });
+
+    it('refuses it at the bundle door too, which is the one an app actually authors', () => {
+      // `defineTranslationBundle` and `stack.translations` both parse through
+      // `TranslationBundleSchema`; #3778's asymmetry was a guard that closed
+      // one door and left the other open.
+      const result = TranslationBundleSchema.safeParse({ 'zh-CN': { settings } });
+      expect(result.success).toBe(false);
+      expect(result.error?.issues.find((i) => i.code === 'unrecognized_keys')?.message ?? '')
+        .toContain('PLATFORM group');
+      expect(() => defineTranslationBundle({ 'zh-CN': { settings } } as never)).toThrow(/PLATFORM group/s);
+    });
+
+    it('still accepts it on the platform face and on the registered `translation` item', () => {
+      // The over-acceptance control for the refusals above: the group did not
+      // leave the contract, it left ONE of its three faces.
+      expect(() => PlatformTranslationDataSchema.parse({ settings })).not.toThrow();
+      expect(() => PlatformTranslationBundleSchema.parse({ 'zh-CN': { settings } })).not.toThrow();
+      expect(() => TranslationItemSchema.parse({ locale: 'zh-CN', settings })).not.toThrow();
+    });
   });
 
   it.each(['fileOrganization', 'messageFormat', 'lazyLoad', 'cache'])(
diff --git a/packages/spec/src/system/translation.zod.ts b/packages/spec/src/system/translation.zod.ts
index a0ae44a6894..fb7ad26f0a9 100644
--- a/packages/spec/src/system/translation.zod.ts
+++ b/packages/spec/src/system/translation.zod.ts
@@ -562,6 +562,45 @@ const TRANSLATION_KEY_GUIDANCE: Record<LegacyObjectFirstKey | 'validationMessage
   namespace: '`namespace` is not part of the translation contract — omit it (ADR-0129 D3 retired the separate namespace declaration platform-wide)',
 };
 
+/**
+ * The per-app door's answer for `settings`, the one group that is
+ * platform-only.
+ *
+ * Written as `guidance` rather than an alias because there is no key on THIS
+ * surface to send the author to: settings copy is not app-authorable at all,
+ * and a rename suggestion would be a signpost into a second rejection — the
+ * exact failure {@link TRANSLATION_KEY_GUIDANCE} was extracted to stop. The
+ * singular `setting` rides the same entry: it was an alias for `settings`
+ * while this door declared it, and an alias whose target the shape no longer
+ * accepts is a suggestion the author cannot take.
+ */
+const PER_APP_SETTINGS_PLATFORM_ONLY =
+  '`settings` is a PLATFORM group, not an application one: it is keyed by '
+  + '`SettingsManifest.namespace`, and a manifest is platform code — an application cannot '
+  + 'declare one, so the only namespaces this key could address are the platform\'s own. '
+  + 'Authored here it deep-merged into the one served translation tree, where it rendered only '
+  + 'where the platform bundle carried no string for that key and locale: wherever both defined '
+  + 'the key the platform\'s own `kernel:ready` contribution arrived later and overwrote it. '
+  + 'Delete the group. Platform settings copy is translated in the platform bundle '
+  + '(`@objectstack/service-settings`\'s `settingsBuiltinTranslations`, typed '
+  + '`PlatformTranslationData`); a key it does not translate falls back to the manifest\'s own '
+  + 'literal, so correct it there rather than filling the gap from an application. For an '
+  + 'application\'s own copy use the ten groups this bundle does declare, in the order it '
+  + "declares them — 'objects', 'apps', 'messages', 'globalActions', 'dashboards', 'datasets', "
+  + "'pages', 'flows', 'metadataForms', 'settingsCommon'. Note the last one: 'settingsCommon' IS "
+  + 'on this face, so the Settings UI shell strings an application may translate (the source '
+  + 'badges, under `settingsCommon.sourceLabels`) are NOT what is being refused here — only the '
+  + "per-namespace manifest copy under 'settings' is. "
+  + 'Run `os migrate meta --from 17` to list the mechanical edits for existing sources; apply '
+  + 'them by hand.';
+
+/** The per-app door's guidance: the shared table plus the platform-only `settings`. */
+const APP_TRANSLATION_KEY_GUIDANCE: Record<string, string> = {
+  ...TRANSLATION_KEY_GUIDANCE,
+  settings: PER_APP_SETTINGS_PLATFORM_ONLY,
+  setting: PER_APP_SETTINGS_PLATFORM_ONLY,
+};
+
 // ────────────────────────────────────────────────────────────────────────────
 // Locale-level Translation Data (per-locale aggregate)
 // ────────────────────────────────────────────────────────────────────────────
@@ -586,18 +625,21 @@ const TRANSLATION_KEY_GUIDANCE: Record<LegacyObjectFirstKey | 'validationMessage
  * `content/docs/protocol/kernel/i18n-standard.mdx`.
  */
 /**
- * The translation groups, as a shape rather than a schema.
+ * The translation groups an APPLICATION may author, as a shape rather than a
+ * schema. Ten groups — the eleventh, `settings`, is platform-only and lives in
+ * {@link platformSettingsShape}.
  *
- * Two schemas need exactly these keys: {@link TranslationDataSchema} (one entry
- * of a file-authored bundle) and {@link TranslationItemSchema} (the registered
- * `translation` metadata type — the same groups plus `locale` and the ADR-0010
- * envelope). The item used to reach them with `.extend()`, which is correct for
- * the *validation* but wrong for the *error*: `.extend()` inherits the strict
- * error map that closed over the keys the BASE was built with, so a typo of
- * `locale` on an item would be rejected with `locale` missing from the
- * candidate list. A shape spread into two `strictObject` calls gives each
- * surface its own full key set — the pattern the six `validation` variants
- * settled on in the same campaign.
+ * Three schemas need exactly these keys: {@link TranslationDataSchema} (one
+ * entry of a per-app file-authored bundle — these ten and no more),
+ * {@link PlatformTranslationDataSchema} (these ten plus `settings`) and
+ * {@link TranslationItemSchema} (the registered `translation` metadata type —
+ * the platform face plus `locale` and the ADR-0010 envelope). The item used to
+ * reach them with `.extend()`, which is correct for the *validation* but wrong
+ * for the *error*: `.extend()` inherits the strict error map that closed over
+ * the keys the BASE was built with, so a typo of `locale` on an item would be
+ * rejected with `locale` missing from the candidate list. A shape spread into
+ * separate `strictObject` calls gives each surface its own full key set — the
+ * pattern the six `validation` variants settled on in the same campaign.
  *
  * A function, not a `const`: the values reference `lazySchema` proxies, and
  * building the shape eagerly at module load would defeat the laziness those
@@ -652,7 +694,7 @@ const FLOW_SCREEN_FIELD_NO_OPTIONS =
   + '`objects.<object>.fields.<field>.options` uses — cannot address them unambiguously. Author the '
   + "option labels on the node's `config`.";
 
-const translationDataShape = () => ({
+const appTranslationDataShape = () => ({
   /** Object translations */
   objects: z.record(z.string(), ObjectTranslationDataSchema).optional().describe('Object translations keyed by object name'),
 
@@ -1153,67 +1195,6 @@ const translationDataShape = () => ({
     })).optional().describe('Screen translations keyed by screen node id (`FlowNode.id`, the client\'s `ScreenSpec.nodeId`)'),
   })).optional().describe('Screen-flow translations keyed by flow name'),
 
-  /**
-   * Settings manifest translations keyed by settings namespace
-   * (matches `SettingsManifest.namespace`, e.g. "mail", "branding").
-   *
-   * Convention (auto-resolved by `resolveSettings*` helpers):
-   *   settings.<namespace>.title
-   *   settings.<namespace>.description
-   *   settings.<namespace>.groups.<group_key>.title
-   *   settings.<namespace>.groups.<group_key>.description
-   *   settings.<namespace>.keys.<setting_key>.label
-   *   settings.<namespace>.keys.<setting_key>.help
-   *   settings.<namespace>.keys.<setting_key>.placeholder
-   *   settings.<namespace>.keys.<setting_key>.options.<option_value>
-   *   settings.<namespace>.actions.<action_id>.label
-   *   settings.<namespace>.actions.<action_id>.confirmText
-   *   settings.<namespace>.actions.<action_id>.successMessage
-   */
-  settings: z.record(z.string(), strictObject({
-    surface: 'this settings manifest translation',
-    history: TRANSLATION_HISTORY,
-    aliases: { label: 'title', name: 'title', sections: 'groups', fields: 'keys', settings: 'keys' },
-  }, {
-    title: z.string().optional().describe('Translated settings manifest title'),
-    description: z.string().optional().describe('Translated settings manifest description'),
-    groups: z.record(z.string(), strictObject({
-      surface: 'this settings group translation',
-      history: TRANSLATION_HISTORY,
-      aliases: { label: 'title', name: 'title', heading: 'title' },
-    }, {
-      title: z.string().optional().describe('Translated group title'),
-      description: z.string().optional().describe('Translated group description'),
-    })).optional().describe('Group translations keyed by group key'),
-    keys: z.record(z.string(), strictObject({
-      surface: 'this setting translation',
-      history: TRANSLATION_HISTORY,
-      aliases: { title: 'label', name: 'label', helpText: 'help', hint: 'help', description: 'help', choices: 'options', values: 'options' },
-    }, {
-      label: z.string().optional().describe('Translated setting label'),
-      help: z.string().optional().describe('Translated setting help text'),
-      placeholder: z.string().optional().describe('Translated input placeholder'),
-      options: z.record(z.string(), z.string()).optional()
-        .describe('Enum option value → translated label'),
-    })).optional().describe('Per-setting field translations keyed by setting key'),
-    actions: z.record(z.string(), strictObject({
-      surface: 'this settings action translation',
-      history: TRANSLATION_HISTORY,
-      // Settings actions have no `params`/`resultDialog` — a settings button is
-      // not an action-metadata action. Say so, rather than suggesting the
-      // nearest key and sending the author round again.
-      aliases: { name: 'label', title: 'label', confirm: 'confirmText', success: 'successMessage' },
-      guidance: {
-        params: 'settings actions take no parameters — there is no `params` group to translate',
-        resultDialog: 'settings actions have no result dialog — `resultDialog` translations belong under `objects.<object>._actions` or `globalActions`',
-      },
-    }, {
-      label: z.string().optional().describe('Translated action label'),
-      confirmText: z.string().optional().describe('Translated confirmation prompt'),
-      successMessage: z.string().optional().describe('Translated success toast/message'),
-    })).optional().describe('Action button translations keyed by action id'),
-  })).optional().describe('Settings manifest translations keyed by namespace'),
-
   /**
    * Translations for **metadata-type configuration forms** — the forms
    * used by admins to author objects, fields, agents, flows, etc. in the
@@ -1312,27 +1293,184 @@ const translationDataShape = () => ({
   }).optional().describe('Cross-namespace Settings UI strings'),
 });
 
+/**
+ * The one group that is PLATFORM-ONLY, as a shape rather than a schema.
+ *
+ * `settings` is keyed by `SettingsManifest.namespace`, and a manifest is
+ * platform code (`packages/services/service-settings/src/manifests/*.manifest.ts`)
+ * — an application cannot declare one. So the only namespaces a per-app bundle
+ * could ever address are the PLATFORM's own, and what an app authored there
+ * deep-merged into the single served tree
+ * (`AppPlugin.loadTranslations` → `II18nService.loadTranslations`) that
+ * {@link resolveSettingsTitle} and the console's `useSettingsLabel` read.
+ *
+ * It was therefore not dropped — but nor did it win. `AppPlugin` loads the
+ * app's bundles in its own `start()` (kernel Phase 2) while
+ * `SettingsServicePlugin` contributes the platform's settings translations from
+ * a `kernel:ready` hook (Phase 3), and `deepMerge` gives the LATER source the
+ * leaf. So a per-app entry rendered only where the platform bundle carried no
+ * string for that key and locale, and was overwritten wherever both defined the
+ * key. Platform labels and application labels are separate namespaces (ruling
+ * batch #132 item 2 letter ②), so this shape is spread into
+ * {@link PlatformTranslationDataSchema} and {@link TranslationItemSchema} and
+ * NOT into {@link TranslationDataSchema}, whose door refuses it by name.
+ *
+ * A function, not a `const`, for the same reason
+ * {@link appTranslationDataShape} is one.
+ */
+const platformSettingsShape = () => ({
+  /**
+   * Settings manifest translations keyed by settings namespace
+   * (matches `SettingsManifest.namespace`, e.g. "mail", "branding").
+   *
+   * Convention (auto-resolved by `resolveSettings*` helpers):
+   *   settings.<namespace>.title
+   *   settings.<namespace>.description
+   *   settings.<namespace>.groups.<group_key>.title
+   *   settings.<namespace>.groups.<group_key>.description
+   *   settings.<namespace>.keys.<setting_key>.label
+   *   settings.<namespace>.keys.<setting_key>.help
+   *   settings.<namespace>.keys.<setting_key>.placeholder
+   *   settings.<namespace>.keys.<setting_key>.options.<option_value>
+   *   settings.<namespace>.actions.<action_id>.label
+   *   settings.<namespace>.actions.<action_id>.confirmText
+   *   settings.<namespace>.actions.<action_id>.successMessage
+   */
+  settings: z.record(z.string(), strictObject({
+    surface: 'this settings manifest translation',
+    history: TRANSLATION_HISTORY,
+    aliases: { label: 'title', name: 'title', sections: 'groups', fields: 'keys', settings: 'keys' },
+  }, {
+    title: z.string().optional().describe('Translated settings manifest title'),
+    description: z.string().optional().describe('Translated settings manifest description'),
+    groups: z.record(z.string(), strictObject({
+      surface: 'this settings group translation',
+      history: TRANSLATION_HISTORY,
+      aliases: { label: 'title', name: 'title', heading: 'title' },
+    }, {
+      title: z.string().optional().describe('Translated group title'),
+      description: z.string().optional().describe('Translated group description'),
+    })).optional().describe('Group translations keyed by group key'),
+    keys: z.record(z.string(), strictObject({
+      surface: 'this setting translation',
+      history: TRANSLATION_HISTORY,
+      aliases: { title: 'label', name: 'label', helpText: 'help', hint: 'help', description: 'help', choices: 'options', values: 'options' },
+    }, {
+      label: z.string().optional().describe('Translated setting label'),
+      help: z.string().optional().describe('Translated setting help text'),
+      placeholder: z.string().optional().describe('Translated input placeholder'),
+      options: z.record(z.string(), z.string()).optional()
+        .describe('Enum option value → translated label'),
+    })).optional().describe('Per-setting field translations keyed by setting key'),
+    actions: z.record(z.string(), strictObject({
+      surface: 'this settings action translation',
+      history: TRANSLATION_HISTORY,
+      // Settings actions have no `params`/`resultDialog` — a settings button is
+      // not an action-metadata action. Say so, rather than suggesting the
+      // nearest key and sending the author round again.
+      aliases: { name: 'label', title: 'label', confirm: 'confirmText', success: 'successMessage' },
+      guidance: {
+        params: 'settings actions take no parameters — there is no `params` group to translate',
+        resultDialog: 'settings actions have no result dialog — `resultDialog` translations belong under `objects.<object>._actions` or `globalActions`',
+      },
+    }, {
+      label: z.string().optional().describe('Translated action label'),
+      confirmText: z.string().optional().describe('Translated confirmation prompt'),
+      successMessage: z.string().optional().describe('Translated success toast/message'),
+    })).optional().describe('Action button translations keyed by action id'),
+  })).optional().describe('Settings manifest translations keyed by namespace'),
+});
+
+/**
+ * One locale of a PER-APP translation bundle — `stack.translations`, and
+ * everything {@link defineTranslationBundle} builds.
+ *
+ * Ten groups: every group the platform bundle declares EXCEPT `settings`,
+ * which is platform-only and is refused here by name with
+ * {@link PER_APP_SETTINGS_PLATFORM_ONLY} as the remedy. See
+ * {@link PlatformTranslationDataSchema} for the eleven-group face and for why
+ * the two are separate namespaces.
+ */
 export const TranslationDataSchema = lazySchema(() => strictObject({
   surface: 'this locale of the translation bundle',
   history: TRANSLATION_HISTORY,
-  guidance: TRANSLATION_KEY_GUIDANCE,
-  aliases: { object: 'objects', fields: 'objects', app: 'apps', page: 'pages', dashboard: 'dashboards', dataset: 'datasets', flow: 'flows', setting: 'settings', message: 'messages', strings: 'messages', labels: 'messages', actions: 'globalActions' },
+  guidance: APP_TRANSLATION_KEY_GUIDANCE,
+  // ⛔ No `setting: 'settings'` alias any more: this door no longer declares
+  // `settings`, and an alias prescribing a key the shape rejects is a
+  // suggestion the author cannot take (the `alias-integrity` audit judges
+  // exactly that). Both spellings are answered by `guidance` above instead.
+  aliases: { object: 'objects', fields: 'objects', app: 'apps', page: 'pages', dashboard: 'dashboards', dataset: 'datasets', flow: 'flows', message: 'messages', strings: 'messages', labels: 'messages', actions: 'globalActions' },
   // `locale` lives on the ITEM, not on a bundle entry (the bundle keys ARE the
   // locales). Naming it keeps the suggestion useful for an author who moved a
   // `translation` item into a bundle and left the field behind.
   extraKeys: ['locale'],
-}, translationDataShape()).describe('Translation data for objects, apps, and UI messages'));
+}, appTranslationDataShape()).describe('Per-app translation data for objects, apps, and UI messages'));
 
 export type TranslationData = z.input<typeof TranslationDataSchema>;
 
+/**
+ * One locale of a PLATFORM translation bundle — the eleven groups, `settings`
+ * included.
+ *
+ * The platform's own bundles are code, not authored metadata
+ * (`@objectstack/service-settings`, `@objectstack/platform-objects`, the
+ * plugins), and `settings` is theirs alone: it is keyed by
+ * `SettingsManifest.namespace` and only platform code declares a manifest.
+ *
+ * ## Why this is a second export rather than one type serving both
+ *
+ * It was one type, and one type serving two bundles is what made every
+ * reading of this key wrong. A per-app census asked "does any application
+ * carry `settings` data?", got zero, and read that as "dead key" — while the
+ * platform read it on every Settings screen. The two bundles are separate
+ * namespaces on the platforms this one resembles, and they are separate here
+ * (ruling batch #132 item 2 letter ②, 2026-09-13).
+ *
+ * What the merged type cost, measured rather than assumed: both bundles are
+ * loaded into ONE served tree (`AppPlugin.loadTranslations` and each platform
+ * plugin's `kernel:ready` contribution both call
+ * `II18nService.loadTranslations`, which deep-merges), and
+ * {@link resolveSettingsTitle} and the console's `useSettingsLabel` read that
+ * merged tree. So a per-app `settings` branch did not sit inert — but it did
+ * not override the platform either. The app's bundles arrive in `AppPlugin`'s
+ * `start()` (kernel Phase 2) and the platform's at `kernel:ready` (Phase 3),
+ * and `deepMerge` gives the later source the leaf, so the platform won every
+ * key both defined. What an application actually had was a GAP FILLER on a
+ * namespace it does not own: it rendered only where the platform bundle
+ * carried no string for that key and locale, silently and with no way to tell
+ * the two cases apart.
+ */
+export const PlatformTranslationDataSchema = lazySchema(() => strictObject({
+  surface: 'this locale of the platform translation bundle',
+  history: TRANSLATION_HISTORY,
+  guidance: TRANSLATION_KEY_GUIDANCE,
+  aliases: { object: 'objects', fields: 'objects', app: 'apps', page: 'pages', dashboard: 'dashboards', dataset: 'datasets', flow: 'flows', setting: 'settings', message: 'messages', strings: 'messages', labels: 'messages', actions: 'globalActions' },
+  extraKeys: ['locale'],
+}, {
+  ...appTranslationDataShape(),
+  ...platformSettingsShape(),
+}).describe('Platform translation data — the per-app groups plus the platform-only `settings`'));
+
+export type PlatformTranslationData = z.input<typeof PlatformTranslationDataSchema>;
+
 // ────────────────────────────────────────────────────────────────────────────
 // Translation Bundle (all locales)
 // ────────────────────────────────────────────────────────────────────────────
 
-export const TranslationBundleSchema = lazySchema(() => z.record(LocaleSchema, TranslationDataSchema).describe('Map of locale codes to translation data'));
+export const TranslationBundleSchema = lazySchema(() => z.record(LocaleSchema, TranslationDataSchema).describe('Map of locale codes to per-app translation data'));
 
 export type TranslationBundle = z.input<typeof TranslationBundleSchema>;
 
+/**
+ * The platform's own locale map — {@link PlatformTranslationDataSchema} per
+ * locale. `@objectstack/service-settings`'s `settingsBuiltinTranslations` is
+ * the bundle that needs it; a platform package authoring only groups the
+ * per-app face also declares can keep the narrower {@link TranslationBundle}.
+ */
+export const PlatformTranslationBundleSchema = lazySchema(() => z.record(LocaleSchema, PlatformTranslationDataSchema).describe('Map of locale codes to platform translation data'));
+
+export type PlatformTranslationBundle = z.input<typeof PlatformTranslationBundleSchema>;
+
 /**
  * Type-safe factory for an i18n translation bundle (locale code → translations map). Validates at authoring time via
  * `.parse()` and accepts input-shape config (optional defaults, CEL
@@ -1448,7 +1586,8 @@ export const TranslationItemSchema = lazySchema(() => strictObject({
   guidance: TRANSLATION_KEY_GUIDANCE,
   aliases: { object: 'objects', app: 'apps', page: 'pages', dataset: 'datasets', flow: 'flows', setting: 'settings', message: 'messages', strings: 'messages', labels: 'messages', actions: 'globalActions', lang: 'locale', language: 'locale' },
 }, {
-  ...translationDataShape(),
+  ...appTranslationDataShape(),
+  ...platformSettingsShape(),
   locale: LocaleSchema.describe('BCP-47 locale this item translates (e.g. "zh-CN")'),
 
   // Item identity. Every other registered metadata type declares these;
diff --git a/packages/spec/src/type-alias-convention.pin.test.ts b/packages/spec/src/type-alias-convention.pin.test.ts
index 41c0adefeb1..5620656d047 100644
--- a/packages/spec/src/type-alias-convention.pin.test.ts
+++ b/packages/spec/src/type-alias-convention.pin.test.ts
@@ -275,7 +275,7 @@ import type * as M187 from './shared/duration.zod.js';
 import type * as M188 from './ai/build-progress.zod.js';
 
 // ---------------------------------------------------------------------------
-// 787 isomorphic aliases: `z.input` === `z.infer`, so no `XParsed` is declared.
+// 789 isomorphic aliases: `z.input` === `z.infer`, so no `XParsed` is declared.
 //
 // That number is machine-checked, not hand-kept. The runtime companion at the
 // bottom of this file recomputes the pin count from the source and asserts that
@@ -1259,6 +1259,11 @@ export type Iso651 = Assert<Eq< z.input< typeof M152.ActionResultDialogTranslati
 export type Iso652 = Assert<Eq< z.input< typeof M152.ObjectTranslationDataSchema >, z.infer< typeof M152.ObjectTranslationDataSchema > >>;
 export type Iso653 = Assert<Eq< z.input< typeof M152.TranslationDataSchema >, z.infer< typeof M152.TranslationDataSchema > >>;
 export type Iso654 = Assert<Eq< z.input< typeof M152.TranslationBundleSchema >, z.infer< typeof M152.TranslationBundleSchema > >>;
+// #15178 split the bundle type in two. The platform face is the per-app shape
+// plus one more optional group, so its two states coincide exactly as the
+// per-app face's do — pinned rather than given a permanent `XParsed` synonym.
+export type Iso880 = Assert<Eq< z.input< typeof M152.PlatformTranslationDataSchema >, z.infer< typeof M152.PlatformTranslationDataSchema > >>;
+export type Iso881 = Assert<Eq< z.input< typeof M152.PlatformTranslationBundleSchema >, z.infer< typeof M152.PlatformTranslationBundleSchema > >>;
 export type Iso655 = Assert<Eq< z.input< typeof M152.TranslationConfigSchema >, z.infer< typeof M152.TranslationConfigSchema > >>;
 export type Iso656 = Assert<Eq< z.input< typeof M152.TranslationItemSchema >, z.infer< typeof M152.TranslationItemSchema > >>;
 export type Iso657 = Assert<Eq< z.input< typeof M152.TranslationDiffStatusSchema >, z.infer< typeof M152.TranslationDiffStatusSchema > >>;
@@ -1691,7 +1696,7 @@ describe('ADR-0122 type-alias convention', () => {
   // this title and the section header above the pin list — are now asserted
   // against the recomputed count below, so neither can go stale without a red
   // test naming it.
-  it('still declares all 787 isomorphic pins', () => {
+  it('still declares all 789 isomorphic pins', () => {
     // The truth of each pin is proved by tsc, not here — an `Assert<Eq<...>>`
     // that stops holding is a compile error with the alias named. What tsc
     // cannot notice is a pin that was DELETED: removing the assertion removes
@@ -2283,7 +2288,20 @@ describe('ADR-0122 type-alias convention', () => {
     // `AnalyticsQuerySchema.shape` — already pinned isomorphic as Iso300 — and
     // the four it adds carry no default, transform, catch or pipe, so no
     // `XParsed` is declared and all three come here instead. +3 added.
-    expect(pins).toHaveLength(787);
+    //
+    // 787 -> 789 is #15178's translation bundle split (system/translation.zod.ts,
+    // module slot M152): `PlatformTranslationDataSchema` and
+    // `PlatformTranslationBundleSchema`, the (RISE) case twice. The platform
+    // face is the per-app shape plus one more `.optional()` group and the
+    // bundle is a `z.record` of it, so neither gains a default or a transform —
+    // the same reason `TranslationDataSchema` and `TranslationBundleSchema`
+    // were already on this list, which is what makes their new siblings belong
+    // here rather than carrying a permanent `XParsed` synonym. +2 added. The
+    // two movements were authored in parallel off the same 784 and both took
+    // Iso877/Iso878; #17551 landed on main first, so its ids stand and this
+    // card's pins renumbered to Iso880/Iso881 — ids are claims about pins, not
+    // positions, so the renumbering asserts nothing new.
+    expect(pins).toHaveLength(789);
 
     // The count is stated in PROSE twice as well — this case's title and the
     // section header above the pin list — and until #6605 nothing read either
diff --git a/scripts/check-i18n-walk-parity.mjs b/scripts/check-i18n-walk-parity.mjs
index 3b92b30c95e..046700805cd 100644
--- a/scripts/check-i18n-walk-parity.mjs
+++ b/scripts/check-i18n-walk-parity.mjs
@@ -55,8 +55,9 @@
  *             over one fixture that authors a member of every group. The
  *             walker's own output, not a transcription of its header.
  *   ledger    the groups that legitimately have no extractor face at all, each
- *             carrying the REASON. Holds three entries by the 2026-09-04
- *             ruling, and only shrinks from there (below).
+ *             carrying the REASON. Filled with three entries by the 2026-09-04
+ *             ruling and down to two since #15178 paid one off, and it only
+ *             shrinks from there (below).
  *
  * and the assertion is two set differences:
  *
@@ -196,10 +197,15 @@ const DECLARED_WATCH_HINTS = [
  * it — the ⛔ MAINTAINER-ONLY act the unwalked-group message names, performed
  * by the owner it names rather than by a landing author getting past a check.
  *
- * `settings` is the one DEFERRAL among the three, and it says so out loud so
- * that nobody reads the exemption as the answer: its terminal state — a
- * registry-driven emitter on the `metadataForms` precedent, or removal from the
- * per-app schema — is held on #15178.
+ * It held THREE entries until #15178. `settings` was the one DEFERRAL among
+ * them, and it said so out loud so that nobody read the exemption as the
+ * answer. Its terminal state landed on ruling batch #132 item 2 letter ②
+ * (2026-09-13): the translation type split in two, `settings` stayed on the
+ * PLATFORM bundle and left the per-app one — so the group is no longer
+ * declared on the schema this gate reads, the exemption went stale by the
+ * ledger's own `ledger \ declared = ∅` rule, and `LEDGER_CEILING` ratcheted
+ * 3 → 2 in the same PR. That is the ledger working as designed: the deferral
+ * was paid down, not renewed.
  *
  * Read the class-level note above before adding anything here. The one-line
  * version: a red belongs to whoever owns the walker, an entry here is a
@@ -215,12 +221,6 @@ const KNOWN_NO_EXTRACTOR_FACE = Object.freeze({
     'The Settings UI\'s own five source-badge labels (env / global / tenant / user / default) — the '
     + 'console\'s words in every app rather than any app\'s own, ruled out of the per-app bundles on '
     + '#7646.',
-  settings:
-    'Keyed by `SettingsManifest.namespace`, and manifests are platform code '
-    + '(`packages/services/service-settings/src/manifests/*.manifest.ts`), not authored metadata: no stack '
-    + 'config carries them, and no consumer asks for per-app settings translations today. A DEFERRAL, not '
-    + 'a fact — the terminal state (a registry-driven emitter on the `metadataForms` precedent, or removal '
-    + 'from the per-app schema) is held on #15178.',
 });
 
 /**
@@ -229,7 +229,7 @@ const KNOWN_NO_EXTRACTOR_FACE = Object.freeze({
  * act rather than a line nobody re-reads. Shrink-only in both directions — a
  * ceiling above the real size fails as slack, so it can only be walked down.
  */
-const LEDGER_CEILING = 3;
+const LEDGER_CEILING = 2;
 
 /**
  * A reason must be a real sentence. The floor is 24 characters and a
@@ -551,7 +551,7 @@ async function main(wantList) {
  */
 const RECORDED_DECLARED = [
   'apps', 'dashboards', 'datasets', 'flows', 'globalActions', 'messages',
-  'metadataForms', 'objects', 'pages', 'settings', 'settingsCommon',
+  'metadataForms', 'objects', 'pages', 'settingsCommon',
 ];
 const RECORDED_WALKED = [
   'apps', 'dashboards', 'datasets', 'flows', 'globalActions', 'metadataForms', 'objects', 'pages',
@@ -560,7 +560,7 @@ const RECORDED_WALKED = [
  * …and the verdict those two produce against an EMPTY ledger — which, since the
  * 2026-09-04 ruling, is also exactly the shipped ledger's key set.
  */
-const RECORDED_UNWALKED = ['messages', 'settings', 'settingsCommon'];
+const RECORDED_UNWALKED = ['messages', 'settingsCommon'];
 
 // ── The self-test's own battery roster and floor (#13489) ──────────────────
 //
diff --git a/skills/objectstack-i18n/SKILL.md b/skills/objectstack-i18n/SKILL.md
index 02b5032e6fc..842d8694ed6 100644
--- a/skills/objectstack-i18n/SKILL.md
+++ b/skills/objectstack-i18n/SKILL.md
@@ -168,7 +168,9 @@ All translatable content for a single object is aggregated under
 
 Top-level groups alongside `objects`: `apps` (label, description, navigation),
 `messages`, `globalActions` (object-less actions), `dashboards`, `datasets`, `pages`,
-`flows`, `settings`, `metadataForms`, `settingsCommon`.
+`flows`, `metadataForms`, `settingsCommon`. `settings` is **platform-only** — it is
+keyed by a settings manifest's namespace and only the platform declares one, so an
+app bundle carrying it is refused by name.
 
 For the exact Zod shape (and any field that may have been added since), read
 `node_modules/@objectstack/spec/src/system/translation.zod.ts` —