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/hooks/use-auto-tagging.ts

@@ -1,3 +1,4 @@
+import { useLanguage } from '@/lib/i18n'
 import { useState, useEffect, useRef } from 'react';
 import { useDebounce } from './use-debounce';
 import { TagSuggestion } from '@/lib/ai/types';
@@ -9,6 +10,7 @@ interface UseAutoTaggingProps {
 }
 
 export function useAutoTagging({ content, notebookId, enabled = true }: UseAutoTaggingProps) {
+  const { language } = useLanguage();
   const [suggestions, setSuggestions] = useState<TagSuggestion[]>([]);
   const [isAnalyzing, setIsAnalyzing] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -42,7 +44,7 @@ export function useAutoTagging({ content, notebookId, enabled = true }: UseAutoT
         body: JSON.stringify({
           content: contentToAnalyze,
           notebookId: notebookId || undefined,
-          language: document.documentElement.lang || 'en',
+          language: language || document.documentElement.lang || 'en',
         }),
       });