feat: smart note history with manual/auto modes, delete entries, i18n fixes

- Add noteHistoryMode setting (manual default / auto) with DB migration
- Manual mode: commit button in editor toolbar creates snapshots on demand
- Auto mode: smart snapshots with 20-char diff threshold + 5min cooldown,
  structural changes (color, pin, archive, labels) bypass cooldown
- Add delete individual history entries from history modal
- Fix sidebar: Notes nav no longer active on notebook pages
- Fix sidebar icon: replace filled Lightbulb with outlined FileText
- Fix title suggestions: change from amber to sky blue color scheme
- Fix hydration mismatch: add suppressHydrationWarning on locale dates
- Complete i18n: add history, sort, and AI chat translations for all 16 languages
- Translate French AI assistant section (40+ keys) from English to French
- Update README with new features and stack info

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

memento-note/lib/types.ts

@@ -80,6 +80,28 @@ export interface Note {
   searchScore?: number | null;
 }
 
+export interface NoteHistoryEntry {
+  id: string;
+  noteId: string;
+  userId: string;
+  version: number;
+  reason: string | null;
+  title: string | null;
+  content: string;
+  color: string;
+  isPinned: boolean;
+  isArchived: boolean;
+  type: 'text' | 'checklist';
+  checkItems: CheckItem[] | null;
+  labels: string[] | null;
+  images: string[] | null;
+  links: LinkMetadata[] | null;
+  isMarkdown: boolean;
+  size: NoteSize;
+  notebookId: string | null;
+  createdAt: Date;
+}
+
 export type NoteSize = 'small' | 'medium' | 'large';
 
 export interface LabelWithColor {