feat: detection, control and process improvement register linked to incidents

[jusso-dev]

Summary

Implements issue #66: a durable detection / control / process improvement register linked to incidents, post-incident reviews, and playbooks.

This is separate from #64 review_improvement_proposals (lightweight PIR proposals). Those can be promoted into the register via POST /api/v1/improvement-register/from-proposal with immutable source links.

Schema (migration 0039_improvement_register)

• Types: detection_gap, logging_gap, integration_defect, playbook_defect, security_control_gap, process_failure, training_need, documentation_gap
• Status lifecycle: open → in_review → accepted → in_progress → validated → closed, plus reopened / rejected / deferred
• Tables: improvement_register_items, improvement_register_links, improvement_register_events
• Immutable source_* fields + source links (isSource); multi-case links drive recurrenceCount
• Close requires validationMethod + validationEvidence + actor/timestamp; reopen keeps prior proof in event history
• External ticket fields are references only (ticket-sync cannot replace owner, links, status, recurrence, or audit)

API (improvements:read / improvements:write)

Endpoint	Purpose
GET|POST /api/v1/improvement-register	List / create (optional caseId / reviewId)
GET|PATCH /api/v1/improvement-register/{id}	Read / update
POST .../links, DELETE .../links/{linkId}	Link cases/reviews/proposals/playbooks
POST .../close, POST .../reopen	Validated close; reopen preserves history
POST .../ticket-sync	Bounded external ticket ref/sync state
GET .../events	Append-only lifecycle history
POST .../suggestions	Similarity matches with explained fields (autoMerge: false)
GET .../dashboard	Recurring themes, severity, owners, overdue, validation state
POST .../from-proposal	Consume #64 proposal (idempotent)

Case-linked mutations use authorizeCase. Sensitive evidence redacted without view_sensitive on source/linked cases. Fail-closed empty scopes.

Test plan

• npm run test:improvement-register (Postgres via DATABASE_URL)
• tsc --noEmit
• CI green on PR
• Manual: create from case, link second case → recurrence, close with validation, reopen, ticket conflict, promote PIR proposal

Residual risks

• No full drizzle snapshot for 0039 (hand-written SQL + journal entry, same pattern as some prior migrations).
• Parallel open PR feat: restricted stakeholder portal for updates, evidence requests and approvals #98 (stakeholder portal) previously targeted 0038; main already has console as 0038 — this PR uses 0039. If another PR lands 0039 first, renumber before merge.
• No UI surfaces yet (API + core only); dashboard is API-only.
• External ticket sync is a bounded ref API, not a live connector adapter.
• Similarity is token Jaccard (explainable, not semantic embeddings).

Closes #66

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 2bd23fcc-4960-402d-b92e-ca3694c1b25b

📥 Commits

Reviewing files that changed from the base of the PR and between 536eba7 and d21117a.

📒 Files selected for processing (22)

• docs/api.md
• drizzle/0040_improvement_register.sql
• drizzle/meta/_journal.json
• package.json
• scripts/test-improvement-register.ts
• src/app/api/v1/improvement-register/[id]/close/route.ts
• src/app/api/v1/improvement-register/[id]/events/route.ts
• src/app/api/v1/improvement-register/[id]/links/[linkId]/route.ts
• src/app/api/v1/improvement-register/[id]/links/route.ts
• src/app/api/v1/improvement-register/[id]/reopen/route.ts
• src/app/api/v1/improvement-register/[id]/route.ts
• src/app/api/v1/improvement-register/[id]/ticket-sync/route.ts
• src/app/api/v1/improvement-register/dashboard/route.ts
• src/app/api/v1/improvement-register/from-proposal/route.ts
• src/app/api/v1/improvement-register/route.ts
• src/app/api/v1/improvement-register/suggestions/route.ts
• src/db/schema.ts
• src/lib/improvement-register/core.ts
• src/lib/improvement-register/index.ts
• src/lib/improvement-register/similarity.ts
• src/lib/improvement-register/types.ts
• src/lib/scopes.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/issue-66

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