Integrates Passport.js sessions and updates authentication middleware logic in `auth.ts` and `routes.ts`. Replit-Commit-Author: Agent Replit-Commit-Session-Id: c5f0c281-8dd8-4846-b452-4a07bcd21062 Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/9777c70b-fc38-4831-8d6b-78dfffe041b0/d1d8abd3-0b74-4353-84ac-e56e863e16e5.jpg