Refactor Dockerfile to run FastAPI server using uvicorn; add empty __init__.py files for package initialization

Dockerfile

@@ -45,5 +45,5 @@ USER appuser
 # Expose Port 7860 for the FastAPI server
 EXPOSE 7860
 
-# Run the fastapi server directly using python
-CMD ["python", "/app/backend/main.py"]
+# Run the fastapi server using uvicorn
+CMD ["uvicorn", "backend.main:app", "--host", "0.0.0.0", "--port", "7860"]

backend/main.py

@@ -6,7 +6,7 @@ import uvicorn
 from dotenv import load_dotenv
 
 # Import route modules
-from routes import main_router, upload_router, chat_router, store_router
+from . routes import main_router, upload_router, chat_router, store_router
 
 # Load environment variables
 load_dotenv()