Fix deployment: add gunicorn to minimal deps, use start_alwrity_backend.py

backend/render-build.sh

@@ -15,6 +15,7 @@ starlette>=0.40.0,<0.47.0
 sse-starlette<3.0.0
 uvicorn>=0.24.0
 uvicorn[standard]>=0.24.0
+gunicorn>=21.0.0
 python-multipart>=0.0.6
 python-dotenv>=1.0.0
 loguru>=0.7.2

backend/start_alwrity_backend.py

@@ -376,6 +376,7 @@ def start_backend(enable_reload=False, production_mode=False):
             return False
         
         print(f"[DEBUG] Starting uvicorn with host={host} port={port}", flush=True)
+        print("[DEBUG] >>> ABOUT TO CALL UVICORN.RUN() <<<", flush=True)
         
         # Skip video preflight in podcast-only mode to save memory/time
         is_podcast = os.getenv("ALWRITY_ENABLED_FEATURES", "").strip().lower() == "podcast"