v1.6.0: Full multi-language support for navigation actions

- Added translations for all 28 navigation actions in 14 languages
  (en, hu, de, fr, es, it, ja, zh, nl, pt, sv, pl, ko, tr)
- Fixed rule list localization: now uses keyCode+modifiers lookup
  instead of stored text for language-independent matching
- Added L10n observer to MappingRow for live language switching
- Version bump to 1.6.0 (build 7)

Author: badcode64