- Create HelpScreen with all keyboard shortcuts
- Add hardcoded sections for instructions
- Add binding for '?' key to show help
- Support ESC/q/? to close help screen
- Document notification compression feature in help
- Format help with colors and sections (Navigation, Actions, View, Search)
Features:
- Shows all keyboard shortcuts in organized sections
- Quick Actions section explains notification compression
- Configuration instructions for mail.toml
- Modal dialog with close button
- Extracts bindings automatically for display
