feat: Bind Gradio server to 0.0.0.0 for external access

Change:
- Update demo.launch() to bind to 0.0.0.0:7860
- Previously bound to 127.0.0.1 (localhost only)
- Now accessible from external network connections

Configuration:
- server_name="0.0.0.0": Listen on all network interfaces
- server_port=7860: Explicit port specification

Use Cases:
- Docker containers: Accessible from host machine
- Network deployment: Accessible from other devices on LAN
- Remote development: SSH tunneling and port forwarding
- HF Spaces: Compatible with container networking

Local Access:
- http://localhost:7860 (still works)
- http://127.0.0.1:7860 (still works)
- http://<your-ip>:7860 (now works)

Security Note:
- 0.0.0.0 binding exposes service to network
- Use firewall rules for production deployments
- HF Spaces handles security automatically

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

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

app.py

@@ -468,4 +468,4 @@ with gr.Blocks(title="🤖 Multi-Model Chatbot") as demo:
     gr.Markdown(footer)
 
 if __name__ == "__main__":
-    demo.launch()
+    demo.launch(server_name="0.0.0.0", server_port=7860)