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

components/incidents/investigation-form.tsx

@@ -37,6 +37,8 @@ export function InvestigationForm({ incidentId, existingInvestigationId }: Props
   )
   const [findingsText, setFindingsText] = useState('')
   const [rootCause, setRootCause] = useState('')
+  const [alcoholTest, setAlcoholTest] = useState('')
+  const [witnessRefs, setWitnessRefs] = useState<string[]>([''])
   const [complete, setComplete] = useState(false)
   const [saving, setSaving] = useState(false)
   const [error, setError] = useState<string | null>(null)
@@ -61,7 +63,7 @@ export function InvestigationForm({ incidentId, existingInvestigationId }: Props
   async function getAiDraft() {
     setAiDraftLoading(true)
     try {
-      const res = await fetch(`/api/incidents/${incidentId}/ai/rca-draft`, { method: 'POST' })
+      const res = await fetch(`/ims/api/incidents/${incidentId}/ai/rca-draft`, { method: 'POST' })
       if (!res.ok) return
       const draft = await res.json() as {
         five_why_steps: Array<{ why: string; answer: string }>
@@ -92,6 +94,8 @@ export function InvestigationForm({ incidentId, existingInvestigationId }: Props
       method,
       findings_text: findingsText || null,
       root_cause_summary: rootCause || null,
+      alcohol_test_result: alcoholTest || null,
+      witness_statement_refs: witnessRefs.map(w => w.trim()).filter(Boolean),
       five_why_steps: method === 'five_why' ? fiveWhy.filter(s => s.answer) : null,
       fishbone_categories: method === 'fishbone'
         ? fishbone.map(c => ({ ...c, causes: c.causes.filter(Boolean) })).filter(c => c.causes.length > 0)
@@ -100,13 +104,13 @@ export function InvestigationForm({ incidentId, existingInvestigationId }: Props
 
     let res: Response
     if (existingInvestigationId) {
-      res = await fetch(`/api/incidents/${incidentId}/investigation`, {
+      res = await fetch(`/ims/api/incidents/${incidentId}/investigation`, {
         method: 'PATCH',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ ...payload, investigation_id: existingInvestigationId, complete }),
       })
     } else {
-      res = await fetch(`/api/incidents/${incidentId}/investigation`, {
+      res = await fetch(`/ims/api/incidents/${incidentId}/investigation`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify(payload),
@@ -207,6 +211,45 @@ export function InvestigationForm({ incidentId, existingInvestigationId }: Props
         </div>
       )}
 
+      <div>
+        <label className="block text-sm font-medium text-gray-700 mb-1">Alcohol / Urine Test Result</label>
+        <select
+          value={alcoholTest}
+          onChange={e => setAlcoholTest(e.target.value)}
+          className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm"
+        >
+          <option value="">Not applicable / not conducted</option>
+          <option value="negative">Negative</option>
+          <option value="positive">Positive</option>
+          <option value="refused">Refused</option>
+          <option value="pending">Result pending</option>
+        </select>
+      </div>
+
+      <div>
+        <label className="block text-sm font-medium text-gray-700 mb-1">Witness Statements</label>
+        <p className="text-xs text-gray-400 mb-2">
+          Reference each statement (witness name, document ref). Upload scans as investigation-stage evidence.
+        </p>
+        {witnessRefs.map((ref, i) => (
+          <input
+            key={i}
+            type="text"
+            value={ref}
+            onChange={e => setWitnessRefs(witnessRefs.map((w, j) => (j === i ? e.target.value : w)))}
+            placeholder="e.g. Ali bin Ahmad — statement dated 12/07/2026"
+            className="w-full rounded border border-gray-300 px-2 py-1.5 text-sm mb-1.5"
+          />
+        ))}
+        <button
+          type="button"
+          onClick={() => setWitnessRefs([...witnessRefs, ''])}
+          className="text-xs text-blue-600 hover:underline"
+        >
+          + Add witness statement
+        </button>
+      </div>
+
       <div>
         <label className="block text-sm font-medium text-gray-700 mb-1">Key Findings</label>
         <textarea