refactor(docker): standardize docker network name to 'frontend'

- Replace 'traefik-network' with 'frontend' in docker-compose.traefik.yml
- Replace 'traefik-network' with 'frontend' in switch-to-traefik.sh
- Replace 'your-main-network' with 'frontend' in DOCKER_DEPLOYMENT.md examples
- Ensure consistency across Docker configuration and documentation

Co-Authored-By: Claude <noreply@anthropic.com>

DOCKER_DEPLOYMENT.md

@@ -175,10 +175,10 @@ services:
       - "traefik.http.routers.bttoxin-backend.entrypoints=websecure"
       # ... 其他 label
     networks:
-      - your-main-network
+      - frontend
 
 networks:
-  your-main-network:
+  frontend:
     external: true
 ```