Add Web UI and Zero-Configuration Startup to Bifrost

This PR introduces a built-in web interface and zero-configuration startup to Bifrost, making it significantly easier to use and manage. Users can now start Bifrost with a single command and configure everything visually without editing JSON files.

Key Changes:

• Added a beautiful web UI for visual configuration, real-time monitoring, and analytics
• Implemented zero-configuration startup - no config files needed to get started
• Simplified Docker usage with automatic app directory and volume management
• Added dynamic provider configuration via web UI and API endpoints
• Auto-detection of common environment variables (OPENAI_API_KEY, etc.)
• Updated documentation to reflect the new simplified workflow
• Improved persistence with app directory concept for storing configuration and logs
• Enhanced the README with emoji-based feature highlights for better readability

Usage Examples:

# Start with zero configuration
docker run -p 8080:8080 maximhq/bifrost

# Open web interface
open http://localhost:8080

This change maintains backward compatibility with file-based configuration while providing a much more user-friendly experience for new and existing users.