- redesign voice recorder UI with modern responsive layout and dark mode support

- implement full waveform visualization with real-time volume meter
- add keyboard shortcuts for common recording actions
- improve recording management with rename, download and better playback controls
- add toast notifications for user feedback
- implement modal dialogs for recording rename and keyboard shortcuts info
- add audio processing options (noise reduction, auto gain)
- enhance error handling with user-friendly messages
- improve recording metadata (duration, size, format)
- optimize performance with canvas resizing and animation frame handling

Author: TobiasMue91