feat: add Docker deployment support and fix /users/me endpoint

- Add docker/ directory with Dockerfile for backend and frontend
- Backend: pytorch/pytorch CUDA base image with all qwen_tts deps
- Frontend: multi-stage nginx build with /api/ proxy to backend
- docker-compose.yml (CPU) + docker-compose.gpu.yml (GPU overlay)
- Fix /users/me returning 404 due to missing route (was caught by /{user_id})
- Update .gitignore to exclude docker/models, docker/data, docker/.env
- Update README and README.zh.md with Docker deployment instructions

Images: bdim404/qwen3-tts-backend, bdim404/qwen3-tts-frontend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

qwen3-tts-backend/api/users.py

@@ -78,6 +78,14 @@ async def create_user(
 
     return user
 
+@router.get("/me", response_model=User)
+@limiter.limit("30/minute")
+async def get_current_user_info(
+    request: Request,
+    current_user: User = Depends(get_current_user)
+):
+    return current_user
+
 @router.get("/{user_id}", response_model=User)
 @limiter.limit("30/minute")
 async def get_user(