fix: Disable queue system to resolve HTTP/2 SSE errors

- Add concurrency_limit=None to ChatInterface
- Add enable_queue=False to demo.launch()
- Prevents ERR_HTTP2_PROTOCOL_ERROR on HF Spaces
- Removes /gradio_api/queue/data SSE endpoint
- Removes /gradio_api/heartbeat connection checks

This fixes persistent HTTP/2 protocol errors even on PRO tier
by disabling Server-Sent Events (SSE) streaming entirely.
Trade-off: No token-by-token streaming, but stable operation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app.py

@@ -275,6 +275,7 @@ with gr.Blocks(
             elem_classes="chatbot-input",
             show_label=False,
         ),
+        concurrency_limit=None,  # 큐 비활성화로 HTTP/2 SSE 오류 방지
     )
 
     # Examples section with model switching
@@ -358,4 +359,5 @@ with gr.Blocks(
     )
 
 if __name__ == "__main__":
-    demo.launch()
+    # 큐 완전 비활성화로 HTTP/2 프로토콜 오류 방지
+    demo.launch(enable_queue=False)