feat: mount Gradio UI at /ui instead of root

- Prevents routing conflicts with API endpoints
- Root '/' now returns service info JSON with endpoint links
- More robust separation of concerns (API vs UI)

main.py

@@ -289,9 +289,26 @@ async def oauth_client() -> JSONResponse:
     )
 
 
-# Build Gradio UI and mount as catch-all (after all API routes)
+# Build Gradio UI and mount under /ui
 gradio_app = build_gradio_ui()
-app.mount("/", gradio_app.app)
+app.mount("/ui", gradio_app.app)
+
+
+# Root endpoint - simple redirect/info
+@app.get("/")
+async def root_info() -> JSONResponse:
+    return JSONResponse(
+        {
+            "service": "A2A Cloud Coder",
+            "status": "running",
+            "endpoints": {
+                "health": "/health",
+                "a2a_api": "/a2a/v1",
+                "agent_card": "/.well-known/agent-card.json",
+                "ui": "/ui",
+            },
+        }
+    )
 
 
 if __name__ == "__main__":