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.yml

@@ -3,51 +3,46 @@ services:
     build:
       context: .
       dockerfile: docker/Dockerfile
+      args:
+        BUILDKIT_INLINE_CACHE: 0
+    pull_policy: build
     container_name: normogen-backend
     ports:
-      - '6800:8000'
+      - '8000:8000'
     environment:
       - RUST_LOG=info
       - SERVER_PORT=8000
+      - SERVER_HOST=0.0.0.0
       - MONGODB_URI=mongodb://mongodb:27017
-      - DATABASE_NAME=normogen
-    env_file:
-      - .env
+      - MONGODB_DATABASE=normogen
+      - JWT_SECRET=${JWT_SECRET:-please-change-this-in-production}
     depends_on:
       mongodb:
         condition: service_healthy
     networks:
       - normogen-network
     restart: unless-stopped
-    deploy:
-      resources:
-        limits:
-          cpus: '1.0'
-          memory: 1000M
-    healthcheck:
-      test: ['CMD', 'wget', '--no-verbose', '--tries=1', '--spider', 'http://localhost:8000/health']
-      interval: 30s
-      timeout: 10s
-      retries: 3
-      start_period: 40s
+    # Disable DNS search domain to fix hostname resolution
+    dns_search: []
   mongodb:
     image: mongo:6.0
     container_name: normogen-mongodb
-    ports:
-      - '27017:27017'
     environment:
       - MONGO_INITDB_DATABASE=normogen
     volumes:
       - mongodb_data:/data/db
     networks:
       - normogen-network
-    restart: unless-stopped
     healthcheck:
-      test: ['CMD', 'mongosh', '--eval', 'db.adminCommand.ping()']
-      interval: 10s
-      timeout: 5s
+      test: |
+        echo 'db.runCommand("ping").ok' | mongosh localhost:27017/test --quiet
+      interval: 30s
+      timeout: 10s
       retries: 5
-      start_period: 10s
+      start_period: 40s
+    restart: unless-stopped
+    # Disable DNS search domain to fix hostname resolution
+    dns_search: []
 volumes:
   mongodb_data:
     driver: local