fix(i18n/de): address code review findings

- Remove broken `import type { I18nDictionary } from '../types'` from
  de.ts and de.settings.ts; match the untyped style of fr.ts/fr.settings.ts
- Add `de`/`de-*` case to normalizeLocale() in runtime.ts so browser
  locale auto-detection picks up German without manual Settings change
- Fix ternary indentation in store.ts to match surrounding pl/ja branches

packages/ui/src/lib/i18n/runtime.ts

@@ -60,6 +60,9 @@ export function normalizeLocale(value: string | undefined | null): Locale {
   if (normalized === 'ja' || normalized.startsWith('ja-')) {
     return 'ja';
   }
+  if (normalized === 'de' || normalized.startsWith('de-')) {
+    return 'de';
+  }
   if (normalized === 'pl' || normalized.startsWith('pl-')) {
     return 'pl';
   }