feat(P2+P3): IHF Phase 2 complete; register Phase 3 workplan

Phase 2 — Structured Feedback and Triage (IHUB-WP-0002):
- Schema: annotation_threads, requirement_candidates, triage_states,
  reviewer_assignments; annotations extended with severity + thread_id
- AnnotationThreadsController: create threads, assign annotations
- RequirementCandidatesController: CRUD, escalation, triage lifecycle,
  reviewer assignment, my-queue
- Annotation severity (low/medium/high/critical) with Tailwind color cues
- TriageDashboardAction on HubsController with autoRefresh
- Integration tests (T01–T09), SCOPE.md updated, docs/phase2-summary.md

Phase 3 — Governance and Decision Linkage (IHUB-WP-0003):
- Workplan registered: 9 tasks, State Hub workstream 5f201ee3

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Web/Routes.hs

@@ -16,5 +16,11 @@ instance AutoRoute InteractionEventsController
 -- Annotations (scoped to widget: /widgets/:widgetId/annotations/)
 instance AutoRoute AnnotationsController
 
+-- Annotation Threads (scoped to widget)
+instance AutoRoute AnnotationThreadsController
+
+-- Requirement Candidates
+instance AutoRoute RequirementCandidatesController
+
 -- Sessions
 instance AutoRoute SessionsController