feat(01-01): configure Auth.js v5 JWT + Credentials, route protection middleware

- Created src/lib/auth.ts with NextAuth JWT strategy, 7-day rolling session, Credentials provider
- Created src/app/api/auth/[...nextauth]/route.ts with GET/POST handlers and force-dynamic
- Created middleware.ts at project root (not src/) protecting /agent/* routes
- Fixed db/index.ts: lazy Proxy singleton prevents neon() crash during Next.js build
- npm run build passes; /api/auth/[...nextauth] renders as Dynamic route

teressa-copeland-homes/src/app/api/auth/[...nextauth]/route.ts

@@ -0,0 +1,5 @@
+import { handlers } from "@/lib/auth";
+
+export const dynamic = "force-dynamic";
+
+export const { GET, POST } = handlers;