feat: Add app.py entrypoint for Hugging Face Spaces integration

app.py

@@ -0,0 +1,8 @@
+import main
+
+# Expose main.app for Hugging Face Spaces Gradio / FastAPI launcher
+app = main.app
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(app, host="0.0.0.0", port=7860)