Phase 1 scaffold: auth for all apps

- Backend: Fastify with two listeners (public + internal), routes, services, DB migration + seed
- client_app: Flutter with BLoC, all auth screens (welcome, display name, register, OTP, force-register)
- mitra_app: Flutter with BLoC, OTP-only login
- control_center: React + Vite, email/password login, mitra/user management, anonymity settings
- Docs: phase1 plan, API contract, client app mockup
- CLAUDE.md and shared memory for all subprojects

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/.env.example

@@ -0,0 +1,12 @@
+# Server
+PUBLIC_PORT=3000
+INTERNAL_PORT=3001
+INTERNAL_HOST=127.0.0.1
+
+# Database
+DATABASE_URL=postgresql://user:password@localhost:5432/halobestie
+
+# Firebase
+FIREBASE_PROJECT_ID=your-firebase-project-id
+FIREBASE_CLIENT_EMAIL=your-service-account@project.iam.gserviceaccount.com
+FIREBASE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n"