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

lib/notifications/in-app.ts

@@ -0,0 +1,42 @@
+import type { SupabaseClient } from '@supabase/supabase-js'
+
+export interface InAppNotification {
+  userId: string
+  title: string
+  link?: string
+  incidentId?: string
+  capaId?: string
+}
+
+// Inserts go through the create_in_app_notification SECURITY DEFINER RPC:
+// notifications_log INSERT is RLS-restricted to elevated roles, but reporters
+// must still be able to trigger alerts to supervisors/HSE.
+export async function createInAppNotifications(
+  supabase: SupabaseClient,
+  notifications: InAppNotification[],
+): Promise<{ created: number }> {
+  const seen = new Set<string>()
+  let created = 0
+
+  for (const n of notifications) {
+    if (!n.userId || !n.title) continue
+    const key = `${n.userId}|${n.title}|${n.incidentId ?? ''}|${n.capaId ?? ''}`
+    if (seen.has(key)) continue
+    seen.add(key)
+
+    const { error } = await supabase.rpc('create_in_app_notification', {
+      p_recipient: n.userId,
+      p_title: n.title,
+      p_link: n.link ?? null,
+      p_incident_id: n.incidentId ?? null,
+      p_capa_id: n.capaId ?? null,
+    })
+    if (error) {
+      console.error('in-app notification error:', error)
+      continue
+    }
+    created++
+  }
+
+  return { created }
+}