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- Fix sidebar: Notes nav no longer active on notebook pages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/locales/zh.json

@@ -1002,7 +1002,29 @@
     "notes.emptyNotebook": "空笔记本",
     "notes.emptyNotebookDesc": "此笔记本没有笔记。点击 + 创建一个。",
     "notes.noNoteSelected": "未选择笔记",
-    "notes.selectOrCreateNote": "从列表中选择笔记或创建新笔记。"
+    "notes.selectOrCreateNote": "从列表中选择笔记或创建新笔记。",
+    "commitVersion": "保存版本",
+    "versionSaved": "版本已保存",
+    "deleteVersion": "删除此版本",
+    "versionDeleted": "版本已删除",
+    "deleteVersionConfirm": "确定永久删除此版本？",
+    "historyMode": "历史模式",
+    "historyModeManual": "手动（提交按钮）",
+    "historyModeAuto": "自动（智能）",
+    "historyModeManualDesc": "使用提交按钮手动创建快照",
+    "historyModeAutoDesc": "智能检测自动创建快照",
+    "history": "历史",
+    "historyRestored": "版本已恢复",
+    "historyEnabled": "历史已启用",
+    "historyDisabledDesc": "您的账户已禁用历史记录。",
+    "enableHistory": "启用历史",
+    "historyEmpty": "暂无版本",
+    "historySelectVersion": "选择一个版本以预览其内容",
+    "sortBy": "排序方式",
+    "sortDateDesc": "日期（最新）",
+    "sortDateAsc": "日期（最早）",
+    "sortTitleAsc": "标题 A → Z",
+    "sortTitleDesc": "标题 Z → A"
   },
   "pagination": {
     "next": "→",