feat(db): phase 4 group 6 — server component pages to Drizzle

Converts all 18 server component page files from Supabase client queries
to Drizzle ORM using asAdmin. Adds getSession() + redirect to the three
pages (hse/incidents, hse/incidents/[id], hse/dashboard) that lacked it.
Maps snake_case component prop shapes explicitly where required.

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

app/(protected)/hse/incidents/[id]/investigation/page.tsx

@@ -2,8 +2,10 @@ export const dynamic = 'force-dynamic'
 
 import { notFound, redirect } from 'next/navigation'
 import Link from 'next/link'
-import { createClient } from '@/lib/supabase/server'
+import { asAdmin } from '@/lib/db/with-user'
 import { getSession } from '@/lib/auth/get-session'
+import { incidents, investigations } from '@/lib/db/schema'
+import { eq, desc } from 'drizzle-orm'
 import { InvestigationForm } from '@/components/incidents/investigation-form'
 
 interface Props {
@@ -16,25 +18,28 @@ export default async function InvestigationPage({ params }: Props) {
   if (!session) redirect(`/login?redirect=/hse/incidents/${id}/investigation`)
   if (!['hse', 'admin'].includes(session.role)) redirect('/hse/incidents')
 
-  const supabase = await createClient()
-
-  const { data: incident } = await supabase
-    .from('incidents')
-    .select('id, reference_no, status')
-    .eq('id', id)
-    .single()
+  const [incident] = await asAdmin(db =>
+    db.select({
+      id: incidents.id,
+      referenceNo: incidents.referenceNo,
+      status: incidents.status,
+    })
+    .from(incidents)
+    .where(eq(incidents.id, id))
+    .limit(1)
+  )
 
   if (!incident) notFound()
-  if (!['triaged', 'investigating'].includes((incident as { status: string }).status))
+  if (!['triaged', 'investigating'].includes(incident.status))
     redirect(`/hse/incidents/${id}`)
 
-  const { data: existing } = await supabase
-    .from('investigations')
-    .select('id')
-    .eq('incident_id', id)
-    .order('created_at', { ascending: false })
+  const [existing] = await asAdmin(db =>
+    db.select({ id: investigations.id })
+    .from(investigations)
+    .where(eq(investigations.incidentId, id))
+    .orderBy(desc(investigations.createdAt))
     .limit(1)
-    .maybeSingle()
+  )
 
   return (
     <main className="max-w-2xl mx-auto px-4 py-6">
@@ -42,10 +47,10 @@ export default async function InvestigationPage({ params }: Props) {
         ← Back to incident
       </Link>
       <h1 className="text-xl font-bold text-gray-900 mb-1">Investigation Workspace</h1>
-      <p className="text-sm text-gray-500 mb-6">{(incident as { reference_no: string | null }).reference_no ?? id}</p>
+      <p className="text-sm text-gray-500 mb-6">{incident.referenceNo ?? id}</p>
       <InvestigationForm
         incidentId={id}
-        existingInvestigationId={(existing as { id: string } | null)?.id ?? null}
+        existingInvestigationId={existing?.id ?? null}
       />
     </main>
   )