chore(changeset): flow trigger key guidance

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017RbbUMnxkUnWhE4j94v8FE

Author: os-sam

.changeset/flow-trigger-key-start-node-guidance.md

@@ -0,0 +1,39 @@
+---
+"@objectstack/spec": patch
+---
+
+fix(spec): a top-level flow `trigger` / `triggerType` is now sent to the START node's `config`, not to a `type` rename
+
+`FlowSchema`'s alias table pointed both keys at `type`, so a flow carrying a
+top-level trigger block was refused with the rename `trigger` → `type`.
+That rename cannot be taken: `type` is the flow KIND
+(`autolaunched` | `record_change` | `schedule` | `screen` | `api`), so an author
+who followed the advice landed on
+`Invalid option: expected one of "autolaunched"|…` one round later, with the
+trigger binding still nowhere — and a `.strict()` refusal carries exactly one
+actionable sentence.
+
+The trigger does not move to `type`. It binds on the START node's `config`, as
+`{ objectName, triggerType, condition }` with a `record-*` token such as
+`record-after-create` — the shape the automation engine and the authoring-time
+`resolveFlowTriggerKind` both read. Both keys are `guidance` entries now, beside
+the `object` / `objectName` / `schedule` prescriptions that already name that
+config, so the rejection says where the binding really lives instead of
+prescribing a name:
+
+```
+Unrecognized key(s) on this flow: `trigger`.
+  • `trigger` is not a Flow field — a record-change flow binds its trigger on
+    the START node's `config` (`{ objectName, triggerType, condition }`, where
+    `triggerType` is a `record-*` token such as `record-after-create`), not at
+    the flow top level; the flow-level `type` names the flow kind
+    (`record_change`), not the binding.
+```
+
+No accept/reject behaviour changes: a top-level `trigger` / `triggerType` was
+refused before and is refused now, and `FlowSchema`'s accepted keys and its
+`type` enum are untouched — only the prescription the refusal carries. One
+measured consequence of dropping the alias row: the guidance channel matches the
+exact authored spelling (case folding is the rename channel's job), so a
+non-canonical spelling such as `triggertype` now gets the bare rejection rather
+than the rename it cannot take.