- Implement keybindingMigration utility to convert old format to new format
- Add migration logic in registerUserKeybindings() for backward compatibility
- Update tests to use event.code format in KeyboardEvent creation
- Add comprehensive migration test suite
- Automatically migrate user keybindings on first load after update
This ensures existing user custom keybindings continue working after switching
from event.key to event.code for layout-independent shortcut handling.
Relates to #5252