Remove since this is a new package with no external users:
- SetActionHandler() - use OnMissingKey() instead
- MissingKeyAction type alias - use MissingKey instead
Update tests to use current API.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Move handler functions from mode.go to actions.go:
- OnMissingKey, SetActionHandler, dispatchMissingKey
mode.go now contains only Mode type and constants.
interface.go keeps all types/interfaces.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>