feat(settings): theme scheduler, UI scale, CustomSelect scroll fix

- Time-based theme scheduler: auto-switches between day/night theme
  based on configurable times; setInterval re-checks every minute
- UI scale slider (80–150%) via CSS zoom on document root; preset
  buttons aligned to actual slider positions
- CustomSelect: scroll listener keeps dropdown anchored on scroll
- All features i18n in 7 languages

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/locales/nb.ts

@@ -571,6 +571,15 @@ export const nbTranslation = {
     seekbarParticletrail: 'Partikkelspor',
     seekbarLiquidfill: 'Væskerør',
     seekbarRetrotape: 'Retrotape',
+    themeSchedulerTitle: 'Tidsplanlagt tema',
+    themeSchedulerEnable: 'Aktiver temaplanlegger',
+    themeSchedulerEnableSub: 'Bytter automatisk mellom to temaer basert på tidspunkt',
+    themeSchedulerDayTheme: 'Dagtema',
+    themeSchedulerDayStart: 'Dag starter kl.',
+    themeSchedulerNightTheme: 'Natttema',
+    themeSchedulerNightStart: 'Natt starter kl.',
+    uiScaleTitle: 'Grensesnittskala',
+    uiScaleLabel: 'Zoom',
   },
   changelog: {
     modalTitle: "Nyheter",