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>

Application/Schema.sql

@@ -1,6 +1,8 @@
--- IHF Phase 1 Schema
+-- IHF Phase 1 + Phase 2 Schema
 -- Hub, Widget, WidgetVersion, InteractionEvent, Annotation
+-- Phase 2: AnnotationThread, RequirementCandidate, TriageState, ReviewerAssignment
 -- See workplans/IHUB-WP-0001-ihf-phase1-minimal-interaction-core.md
+-- See workplans/IHUB-WP-0002-ihf-phase2-structured-feedback-and-triage.md
 
 CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
 
@@ -79,13 +81,26 @@ CREATE TRIGGER interaction_events_no_delete
     BEFORE DELETE ON interaction_events
     FOR EACH ROW EXECUTE FUNCTION prevent_interaction_event_mutation();
 
+-- Annotation threads — groups related annotations for triage (Phase 2)
+CREATE TABLE annotation_threads (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    widget_id UUID NOT NULL REFERENCES widgets(id) ON DELETE CASCADE,
+    title TEXT NOT NULL,
+    description TEXT,
+    created_by UUID REFERENCES users(id),
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
 -- Annotations — structured commentary, also append-only by convention
+-- Phase 2 additions: severity, thread_id
 CREATE TABLE annotations (
     id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
     widget_id UUID NOT NULL REFERENCES widgets(id) ON DELETE CASCADE,
     parent_id UUID REFERENCES annotations(id) ON DELETE CASCADE,
     body TEXT NOT NULL,
     category TEXT NOT NULL DEFAULT 'friction',
+    severity TEXT NOT NULL DEFAULT 'medium',
+    thread_id UUID REFERENCES annotation_threads(id) ON DELETE SET NULL,
     actor_id UUID,
     actor_type TEXT NOT NULL DEFAULT 'user',
     widget_state_ref TEXT,
@@ -94,3 +109,42 @@ CREATE TABLE annotations (
 );
 
 CREATE INDEX annotations_widget_id_idx ON annotations (widget_id);
+
+-- Requirement candidates — escalated from annotations/threads (Phase 2)
+CREATE TABLE requirement_candidates (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    title TEXT NOT NULL,
+    description TEXT NOT NULL,
+    source_widget_id UUID NOT NULL REFERENCES widgets(id) ON DELETE RESTRICT,
+    source_thread_id UUID REFERENCES annotation_threads(id) ON DELETE SET NULL,
+    source_annotation_id UUID REFERENCES annotations(id) ON DELETE SET NULL,
+    category TEXT NOT NULL DEFAULT 'friction',
+    status TEXT NOT NULL DEFAULT 'open',
+    created_by UUID REFERENCES users(id),
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
+CREATE INDEX requirement_candidates_widget_id_idx ON requirement_candidates (source_widget_id);
+CREATE INDEX requirement_candidates_status_idx ON requirement_candidates (status);
+
+-- Triage state history — append-only audit trail of status transitions (Phase 2)
+CREATE TABLE triage_states (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    candidate_id UUID NOT NULL REFERENCES requirement_candidates(id) ON DELETE CASCADE,
+    status TEXT NOT NULL,
+    notes TEXT,
+    changed_by UUID REFERENCES users(id),
+    changed_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
+CREATE INDEX triage_states_candidate_id_idx ON triage_states (candidate_id);
+
+-- Reviewer assignments — one reviewer per candidate (Phase 2)
+CREATE TABLE reviewer_assignments (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    candidate_id UUID NOT NULL REFERENCES requirement_candidates(id) ON DELETE CASCADE,
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    assigned_by UUID REFERENCES users(id),
+    assigned_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL,
+    UNIQUE (candidate_id)
+);