feat: RTL/i18n, AI translate+undo, no-refresh saves, settings perf

- RTL: force dir=rtl on LabelFilter, NotesViewToggle, LabelManagementDialog
- i18n: add missing keys (notifications, privacy, edit/preview, AI translate/undo)
- Settings pages: convert to Server Components (general, appearance) + loading skeleton
- AI menu: add Translate option (10 languages) + Undo AI button in toolbar
- Fix: saveInline uses REST API instead of Server Action → eliminates all implicit refreshes in list mode
- Fix: NotesTabsView notes sync effect preserves selected note on content changes
- Fix: auto-tag suggestions now filter already-assigned labels
- Fix: color change in card view uses local state (no refresh)
- Fix: nav links use <Link> for prefetching (Settings, Admin)
- Fix: suppress duplicate label suggestions already on note
- Route: add /api/ai/translate endpoint

keep-notes/components/title-suggestions.tsx

@@ -22,6 +22,7 @@ export function TitleSuggestions({ suggestions, onSelect, onDismiss }: TitleSugg
           <span>{t('titleSuggestions.title')}</span>
         </div>
         <button
+          type="button"
           onClick={onDismiss}
           className="text-amber-600 hover:text-amber-900 dark:text-amber-400 dark:hover:text-amber-200 transition-colors"
         >
@@ -33,6 +34,7 @@ export function TitleSuggestions({ suggestions, onSelect, onDismiss }: TitleSugg
         {suggestions.map((suggestion, index) => (
           <button
             key={index}
+            type="button"
             onClick={() => onSelect(suggestion.title)}
             className={cn(
               "w-full text-left px-3 py-2 rounded-md transition-all",