feat(auth): phase 3 — replace Supabase GoTrue with bcryptjs+jose

Custom auth stack: bcryptjs password hashing (cost 10, GoTrue-compatible),
jose JWT session cookies (edge-safe, 8hr TTL), new API routes for
login/logout/reset/change-password, middleware rewritten to JWT-only
verification with no DB access. All 38 protected pages and API routes
migrated from supabase.auth.getUser() to getSession(). Supabase .from()
queries retained for Phase 4. lib/db/index.ts refactored to lazy Proxy
singleton to avoid module-level throw during Next.js build.

tsc: clean, build: clean, tests: 4/4 passed

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

app/api/incidents/[id]/route.ts

@@ -1,17 +1,16 @@
 import { NextResponse } from 'next/server'
 import { createClient } from '@/lib/supabase/server'
+import { getSession } from '@/lib/auth/get-session'
 
 export const dynamic = 'force-dynamic'
 
 export async function GET(_req: Request, { params }: { params: Promise<{ id: string }> }) {
   const { id } = await params
-  const supabase = await createClient()
-  const { data, error: authError } = await supabase.auth.getUser()
-  if (authError || !data?.user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
-  const user = data.user
+  const session = await getSession()
+  if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
 
-  const { data: profile } = await supabase.from('users').select('role, site_id').eq('id', user.id).single()
-  const role = profile?.role ?? ''
+  const supabase = await createClient()
+  const role = session.role
 
   const { data: incident, error } = await supabase
     .from('incidents')
@@ -33,7 +32,7 @@ export async function GET(_req: Request, { params }: { params: Promise<{ id: str
   }
 
   const reporter = incident.reporter as unknown as { id: string } | null
-  const isOwner = reporter?.id === user.id
+  const isOwner = reporter?.id === session.sub
   const isSiteStaff = ['hse', 'supervisor', 'admin'].includes(role)
   if (!isOwner && !isSiteStaff) {
     return NextResponse.json({ error: 'Forbidden' }, { status: 403 })