app.py

```python
import gradio as gr
import logging

# Existing imports and code (omitted for brevity) remain unchanged until the launch section

if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO)
    logger = logging.getLogger(__name__)
    
    try:
        logger.info("Starting Gradio application on http://127.0.0.1:7860")
        demo.launch(
            share=False,
            server_name="127.0.0.1",
            server_port=7860,
            debug=True  # Enable debug mode for detailed error output
        )
    except Exception as e:
        logger.error(f"Gradio launch failed: {str(e)}")
        logger.info("Trying alternative port 7861...")
        try:
            demo.launch(
                share=False,
                server_name="127.0.0.1",
                server_port=7861,
                debug=True
            )
        except Exception as e2:
            logger.error(f"Gradio launch failed on port 7861: {str(e2)}")
            raise
```

**Changes**:
- Added explicit `server_name="127.0.0.1"` for local binding.
- Enabled `debug=True` for detailed Gradio logs.
- Added a fallback to try port 7861 if 7860 fails.
- Enhanced logging with `logging` module to capture initialization errors.