fix: let Gradio auto-find free port to avoid OSError crash loops

src/apps/_base.py

@@ -336,7 +336,6 @@ def run_app(spec: ProjectSpec) -> int:
     server_port = int(os.environ.get('PORT', '7860'))
     demo.launch(
         server_name=server_name,
-        server_port=server_port,
         show_error=True,
         share=False,
     )