Keyboard controls for segment management and player

Build comprehensive keyboard shortcuts to enhance user efficiency in managing transcription segments and audio playback. Users should be able to:

• Enter edit mode - Enter/Return key

• Delete segments using Delete/Backspace key

• Navigate between segments using Up/Down arrow keys

• Control audio playback play/pause - Space bar,

• Control rewind and forward/back - Left/Right arrow keys

This feature aims to reduce reliance on mouse interactions and speed up the transcription workflow for power users.