- 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
- Unified localStorage key to 'theme-preference' across all components
- Fixed header.tsx using wrong localStorage key ('theme' instead of 'theme-preference')
- Added localStorage hybrid persistence for instant theme changes
- Removed router.refresh() which was causing stale data revert
- Replaced Blue theme with Sepia
- Consolidated auth() calls to prevent race conditions
- Updated UserSettingsData types to include all themes
## Bug Fixes
### Note Card Actions
- Fix broken size change functionality (missing state declaration)
- Implement React 19 useOptimistic for instant UI feedback
- Add startTransition for non-blocking updates
- Ensure smooth animations without page refresh
- All note actions now work: pin, archive, color, size, checklist
### Markdown LaTeX Rendering
- Add remark-math and rehype-katex plugins
- Support inline equations with dollar sign syntax
- Support block equations with double dollar sign syntax
- Import KaTeX CSS for proper styling
- Equations now render correctly instead of showing raw LaTeX
## Technical Details
- Replace undefined currentNote references with optimistic state
- Add optimistic updates before server actions for instant feedback
- Use router.refresh() in transitions for smart cache invalidation
- Install remark-math, rehype-katex, and katex packages
## Testing
- Build passes successfully with no TypeScript errors
- Dev server hot-reloads changes correctly
- Add debounced state updates for title and content (500ms delay)
- Immediate UI updates with delayed history saving
- Prevent one-letter-per-undo issue
- Add cleanup for debounce timers on unmount
