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/note-card.tsx

@@ -169,7 +169,10 @@ export const NoteCard = memo(function NoteCard({
     (state, newProps: Partial<Note>) => ({ ...state, ...newProps })
   )
 
-  const colorClasses = NOTE_COLORS[optimisticNote.color as NoteColor] || NOTE_COLORS.default
+  // Local color state so color persists after transition ends
+  const [localColor, setLocalColor] = useState(note.color)
+
+  const colorClasses = NOTE_COLORS[(localColor || optimisticNote.color) as NoteColor] || NOTE_COLORS.default
 
   // Check if this note is currently open in the editor
   const isNoteOpenInEditor = searchParams.get('note') === note.id
@@ -263,10 +266,10 @@ export const NoteCard = memo(function NoteCard({
   }
 
   const handleColorChange = async (color: string) => {
+    setLocalColor(color) // instant visual update, survives transition
     startTransition(async () => {
       addOptimisticNote({ color })
-      await updateColor(note.id, color)
-      router.refresh()
+      await updateNote(note.id, { color }, { skipRevalidation: false })
     })
   }