feat: Update AGENTS.md and app.py to support GLM-4.7-Flash provider

feat: Add GLM-4.7 provider support with environment variable authentication

feat: Implement custom CSS to adjust Gradio container width and add padding to the main view.

feat: Add Groq API key validation by making an API call and integrate it into the application's login flow.

refactor: overhaul UI for login and main application views, add logout functionality, and update branding.

feat: Implement API key authentication, owner bypass, and rate limiting for the Gradio interface.

Add copy functionality for outputs and error table in Gradio interface

Add initial implementation of English writing assistant with Gradio interface and Groq API integration