- Fix Enter key detection: handle multiple Enter key formats (\n, \r, \r\n)
- Reduce flickering: lower render frequency from 60 FPS to 30 FPS
- Fix menu bar visibility: re-render menu bar after content to prevent overwriting
- Fix content positioning: explicit line positioning for categories and commands
- Fix line shifting: clear lines before writing, control newlines manually
- Limit visible items: prevent overflow with maxVisibleCategories/Commands
- Improve CPU usage: increase sleep interval when no events processed
This fixes:
- Enter key not working for selection
- Strong flickering of the application
- Menu bar not visible or being overwritten
- Top half of selection list not displayed
- Lines being shifted/misaligned
