feat(editor): implement keyboard navigation enhancements

[blouflab]

Keyboard Enhancement Improvements

Summary

This implements keyboard navigation enhancements for the editor component, focusing on word navigation, command history, and improved key bindings.

Changes

1. Word Navigation

• Ctrl+Left/Right Arrow: Navigate word-by-word backward/forward
• Maintains compatibility with Alt+Left/Right and Alt+B/F shortcuts

2. Command History

• Up Arrow: Navigate to previous command in history
• Down Arrow: Navigate to next command in history
• Commands are automatically saved to history when sent

3. Enhanced Key Bindings

• Ctrl+U: Clear current line

Technical Details

• Added WordBackward/WordForward key bindings to textarea keymap
• Implemented history tracking with history slice and index counter
• Updated key binding struct and default keymap configuration
• All changes are keyboard-focused with no mouse functionality included

Testing

• All existing tests pass
• Build compiles successfully
• Manual testing confirms all keyboard shortcuts work as expected

Solving

• Word by word keyboard navigation in chat input doesn't work #641
• Retry button, keybind or command #722

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[blouflab]

I have read the Contributor License Agreement (CLA) and hereby sign the CLA.

[blouflab]

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