feat(desktop): two-way cloud sync with mobile and web

Rewrites the desktop mirror as services/sync/SyncEngine: a persistent
outbox, per-account server-clock keyset cursors with paging, pulls that never
overwrite unsent local edits, deletions both ways through sync_tombstones and
per-row failure isolation. It now covers history titles and favorites,
dictionary, every meeting's memos and documents, memo tags, user commands and
dictation/meeting templates, and registers the desktop as a device that the
phone can disconnect.

Fixes shipped defects: the first pull after sign-in fetched nothing, only
the first meeting's children were pushed, team meetings leaked into the
personal database and lost team_id on re-push, and Realtime never connected
because Electron's Node 20 has no global WebSocket (ws is now the transport).
Anonymous local-mode records are imported into the first account that signs
in. The settings sync section is translated and shows pending/rejected
changes; synced screens reload on app:dataChanged.

packages/i18n/src/locales/zh.json

@@ -522,5 +522,24 @@
   "settings.captionRefine.desc": "本地 AI 会根据上下文修正已确定字幕的空格、标点和听错的词。",
   "settings.captionModel": "实时字幕模型",
   "settings.captionModel.same": "与听写相同",
-  "settings.captionModel.desc": "仅实时字幕使用单独的模型识别，会与听写模型一同加载。"
+  "settings.captionModel.desc": "仅实时字幕使用单独的模型识别，会与听写模型一同加载。",
+  "history.favorite": "收藏",
+  "history.unfavorite": "取消收藏",
+  "cloudSync.title": "云同步",
+  "cloudSync.description": "自动与移动端和网页同步历史、词典、会议、备忘标签、命令和模板。在任一设备上删除，其他设备也会一并删除。",
+  "cloudSync.signIn": "登录",
+  "cloudSync.signedInAs": "已登录：{{email}}",
+  "cloudSync.noEmail": "无邮箱",
+  "cloudSync.lastSync": "上次同步：{{time}}",
+  "cloudSync.never": "尚未同步",
+  "cloudSync.upToDate": "所有更改均已上传",
+  "cloudSync.pending": "{{count}} 项更改等待上传",
+  "cloudSync.failed": "服务器拒绝了 {{count}} 项更改 —「立即同步」会重试",
+  "cloudSync.syncNow": "立即同步",
+  "cloudSync.syncing": "正在同步…",
+  "cloudSync.signOut": "退出登录",
+  "cloudSync.browserPending": "请在浏览器中完成登录。",
+  "cloudSync.signedOut": "已退出登录。本机上的记录会保留。",
+  "cloudSync.done": "同步完成（已应用 {{count}} 项）",
+  "cloudSync.doneWithErrors": "同步完成（已应用 {{count}} 项，{{errors}} 项失败 — 下次同步时重试）"
 }