* feat(i18n): add Transloco translation framework and translate all settings tabs (EN/ES)
* feat(i18n): translate shared, layout, dashboard, library-creator, and app-root components (EN/ES) and scaffold 7 new languages
* feat(i18n): translate bookdrop and metadata components (EN/ES), remove i18n-audit from tracking
* fix(i18n): deep-merge English as fallback base for incomplete language translations
