Fix Docker networking and add graceful MongoDB error handling

- Fix DNS resolution: Removed invalid dns_search configuration
- Add graceful MongoDB connection error handling
- Set restart policy to 'unless-stopped' for both services
- Add development helper scripts (start-dev.sh, stop-dev.sh)
- Update Docker Compose configurations for development
- Restore main.rs from git history
- Backend now logs MongoDB errors without crashing

All containers now start successfully with proper DNS resolution
on the dedicated normogen-network.

backend/docker-compose.dev.yml

@@ -11,7 +11,6 @@ services:
       - '6500:8000'
     volumes:
       - ./src:/app/src
-      # Mount a volume to capture logs
       - startup-logs:/tmp
     environment:
       - RUST_LOG=debug
@@ -26,8 +25,8 @@ services:
         condition: service_healthy
     networks:
       - normogen-network
-    # DISABLE RESTART TEMPORARILY TO DEBUG
-    restart: "no"
+    restart: unless-stopped
+
   mongodb:
     image: mongo:6.0
     container_name: normogen-mongodb-dev
@@ -47,11 +46,14 @@ services:
       timeout: 5s
       retries: 5
       start_period: 60s
+    restart: unless-stopped
+
 volumes:
   mongodb_dev_data:
     driver: local
   startup-logs:
     driver: local
+
 networks:
   normogen-network:
     driver: bridge