refactor: 个人自用，移除登录与云同步全链路

站点只给本人用，云乐坊 SSO 授权、收藏/历史云同步、获客归因和账号切换记账都没有收益，却被登录状态检查和同步失败提示持续打扰。

- 删除 useYunlefunAuth / yunlefunAuth / yunlefunSsoConfig / yunlefunAuth 适配器、useUserDataSync / userDataSync / userData 适配器、三个 client 插件与 /auth/callback 回调页
- 抽出 adapters/cloudbase.ts，让「反馈一下」和匿名筛选信号不再依赖登录态；cook-feedback 云函数保留
- 删除 cook-user-data 云函数与 cook_user_data 权限规则，移除 @yunlefun/sso 依赖
- 「我的」页删掉登录按钮、账号卡、四个统计格和退出登录；「关于」页删掉项目作者、致谢名单和上游宣传链接
- 本地收藏/历史与导出导入保留，删除同步专用的 lastUid 记账

取舍见 docs/decisions/0005-drop-login-and-sync.md

apps/web/app/composables/store/userData.ts

@@ -1,5 +1,4 @@
 import type { UserData, UserDataExportFile } from '~/utils/userData'
-import type { UserDataLocal } from '~/utils/userDataSync'
 import {
   createEmptyUserData,
   createUserDataExport,
@@ -32,22 +31,12 @@ export function writeLocalUserData(data: UserData): void {
   }
 }
 
-export const localUserData: UserDataLocal = {
-  read: readLocalUserData,
-  write: writeLocalUserData,
-  readLastUid: () => userDataMeta.value.lastUid ?? '',
-  writeLastUid: (uid) => {
-    if (userDataMeta.value.lastUid !== uid)
-      userDataMeta.value = { ...userDataMeta.value, lastUid: uid }
-  },
-}
-
 export function exportLocalUserData(now = Date.now()): UserDataExportFile {
   return createUserDataExport(mergeUserData(readLocalUserData(), createEmptyUserData(), now), now)
 }
 
 /**
- * Merge an exported file into local data, using the same rules as cloud sync.
+ * Merge an exported file into local data.
  * Returns null when the text is not a Cook export.
  */
 export function importLocalUserData(text: string, now = Date.now()): { favorites: number, histories: number } | null {