Fix: copy app.py not main.py, import from app.main

Dockerfile

@@ -11,7 +11,7 @@ RUN pip install --no-cache-dir -r requirements_space.txt
 
 COPY app ./app
 COPY frontend ./frontend
-COPY main.py .
+COPY app.py .
 
 ENV PYTHONPATH=/app
 ENV PYTHONUNBUFFERED=1

app.py

@@ -26,7 +26,7 @@ os.environ["PYTHONUNBUFFERED"] = "1"
 
 logger.info("Loading backend app...")
 try:
-    from main import app as backend_app
+    from app.main import app as backend_app
     logger.info("Backend loaded successfully")
 except Exception as e:
     logger.error(f"Failed to load backend: {e}")