feat: Phase 5 & 6 — usability, compliance hardening, analytics

Phase 5 (usability + compliance):
- In-app notification bell/badge: migration 016 adds read state + per-user
  RLS + create_in_app_notification SECURITY DEFINER RPC; /api/notifications;
  wired into incident creation, CAPA assign/verify, escalation cron
- Incident closure: new POST /api/incidents/[id]/close (requires verification
  status + all CAPAs verified); migration 017 locks closed incidents at DB
  level (update/delete triggers) with append-only incident_addenda + UI panel
- Server-side pagination on HSE/supervisor incident inboxes (.range, 25/page)
- Investigation form: alcohol/urine test result + witness statement refs
  (existing schema columns, now editable)
- Type-specific intake fields: migration 018 adds incidents.type_details
  JSONB; whitelist validation; environmental/asset/security/fire field
  groups in report form; EN/MS/ZH labels; offline queue support
- JKKP 8 annual register CSV export (/api/reports/jkkp8) + dashboard button
  + January statutory deadline banner
- Admin page: user invite (service-role client), role/site/active management,
  site + zone CRUD with QR report links — replaces Phase 0 stub
- Evidence gallery thumbnails via Supabase render transform with fallback

Phase 6 (analytics):
- 12-month stacked trend chart (leading/lagging/other) + top root causes
  (lib/dashboard/trends.ts pure helpers)
- AI rising-risk zones: /api/dashboard/ai/risk-flags aggregates 90-day
  zone stats, claude-opus-4-8 forced tool_use, panel on HSE + management
  dashboards, suggestion audit-logged

Also fixes 9 pre-existing missing /ims basePath prefixes in client fetches
and download links.

132 tests passing, tsc clean, next build clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CPf5Rc8QPx6V8KLEEgfKEQ

supabase/migrations/20260712000016_in_app_notifications.sql

@@ -0,0 +1,50 @@
+-- supabase/migrations/20260712000016_in_app_notifications.sql
+-- Phase 5: in-app notification bell — read state, content columns, per-user RLS,
+-- and a SECURITY DEFINER writer so non-elevated reporters can trigger alerts.
+
+ALTER TABLE notifications_log
+  ADD COLUMN recipient_user_id UUID REFERENCES users(id),
+  ADD COLUMN read_at           TIMESTAMPTZ,
+  ADD COLUMN title             TEXT,
+  ADD COLUMN link              TEXT;
+
+CREATE INDEX notifications_in_app_unread_idx
+  ON notifications_log (recipient_user_id, sent_at DESC)
+  WHERE channel = 'in_app' AND read_at IS NULL;
+
+-- Users see their own in-app notifications (elevated read policy already exists)
+CREATE POLICY "notifications_read_own" ON notifications_log
+  FOR SELECT
+  USING (recipient_user_id = auth.uid());
+
+-- Users may only mark their own notifications read
+CREATE POLICY "notifications_update_own" ON notifications_log
+  FOR UPDATE
+  USING (recipient_user_id = auth.uid())
+  WITH CHECK (recipient_user_id = auth.uid());
+
+-- Writer RPC: INSERT policy on notifications_log is elevated-roles-only, but a
+-- reporter submitting an incident must notify supervisors/HSE. Mirrors write_audit_log.
+CREATE OR REPLACE FUNCTION public.create_in_app_notification(
+  p_recipient   UUID,
+  p_title       TEXT,
+  p_link        TEXT DEFAULT NULL,
+  p_incident_id UUID DEFAULT NULL,
+  p_capa_id     UUID DEFAULT NULL
+)
+RETURNS void
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+BEGIN
+  IF auth.uid() IS NULL THEN
+    RAISE EXCEPTION 'authentication required';
+  END IF;
+
+  INSERT INTO public.notifications_log
+    (channel, recipient, recipient_user_id, title, link, incident_id, capa_id)
+  VALUES
+    ('in_app', p_recipient::text, p_recipient, p_title, p_link, p_incident_id, p_capa_id);
+END;
+$$;

supabase/migrations/20260712000017_closure_lock_addenda.sql

@@ -0,0 +1,57 @@
+-- supabase/migrations/20260712000017_closure_lock_addenda.sql
+-- Phase 5: closed incidents become immutable (addenda-only), per PRD §4 Phase 4.
+
+CREATE TABLE incident_addenda (
+  id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  incident_id UUID NOT NULL REFERENCES incidents(id),
+  author      UUID NOT NULL REFERENCES users(id),
+  body        TEXT NOT NULL,
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX incident_addenda_incident_idx ON incident_addenda(incident_id);
+
+ALTER TABLE incident_addenda ENABLE ROW LEVEL SECURITY;
+
+CREATE POLICY "addenda_read" ON incident_addenda
+  FOR SELECT
+  USING (
+    auth_user_role() IN ('hse', 'admin', 'supervisor', 'management')
+    OR EXISTS (
+      SELECT 1 FROM incidents i
+      WHERE i.id = incident_id AND i.reported_by = auth.uid()
+    )
+  );
+
+CREATE POLICY "addenda_insert" ON incident_addenda
+  FOR INSERT
+  WITH CHECK (
+    author = auth.uid()
+    AND auth_user_role() IN ('hse', 'admin', 'supervisor')
+  );
+
+-- No UPDATE/DELETE policies: addenda are append-only.
+
+-- DB-level lock: once closed, the incident row cannot change or be deleted.
+CREATE OR REPLACE FUNCTION public.prevent_closed_incident_change()
+RETURNS TRIGGER
+LANGUAGE plpgsql
+SECURITY DEFINER
+SET search_path = public
+AS $$
+BEGIN
+  RAISE EXCEPTION 'incident % is closed and locked — add an addendum instead', OLD.id;
+END;
+$$;
+
+CREATE TRIGGER incidents_closed_lock_update
+  BEFORE UPDATE ON incidents
+  FOR EACH ROW
+  WHEN (OLD.status = 'closed')
+  EXECUTE FUNCTION prevent_closed_incident_change();
+
+CREATE TRIGGER incidents_closed_lock_delete
+  BEFORE DELETE ON incidents
+  FOR EACH ROW
+  WHEN (OLD.status = 'closed')
+  EXECUTE FUNCTION prevent_closed_incident_change();

supabase/migrations/20260712000018_type_details.sql

@@ -0,0 +1,5 @@
+-- supabase/migrations/20260712000018_type_details.sql
+-- Phase 5: type-specific intake fields (PRD §3 — each incident type has its own
+-- lightweight form). Stored as validated JSONB; keys whitelisted in app code.
+
+ALTER TABLE incidents ADD COLUMN type_details JSONB;