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/page.tsx

@@ -2,25 +2,16 @@
 export const dynamic = 'force-dynamic'
 
 import { redirect } from 'next/navigation'
-import { createClient } from '@/lib/supabase/server'
+import { getSession } from '@/lib/auth/get-session'
 import { getRoleHome, isValidRole, type UserRole } from '@/lib/auth/roles'
 
 export default async function RootPage() {
-  const supabase = await createClient()
-  const {
-    data: { user },
-  } = await supabase.auth.getUser()
+  const session = await getSession()
 
-  if (!user) redirect('/login')
+  if (!session) redirect('/login')
 
-  const { data: profile } = await supabase
-    .from('users')
-    .select('role')
-    .eq('id', user.id)
-    .single()
-
-  if (profile?.role && isValidRole(profile.role)) {
-    redirect(getRoleHome(profile.role as UserRole))
+  if (session.role && isValidRole(session.role)) {
+    redirect(getRoleHome(session.role as UserRole))
   }
 
   redirect('/login')