feat(admin): embed slot management with code snippet

P4b Task 5：/system/embed-slots 管理页（Task 8/9 页面模式：useCursorList
游标累积 + 对话框治理）。列表（名称/绑定相册/启停/configVersion/更新时间，
启停开关行内 PATCH → configVersion+1 toast 提示）+ 新建/编辑对话框
（设置表单位置/尺寸/间隔/语言/默认收起，intervalMs 契约区间夹取；编辑按
整体替换语义提交完整 settings）+ 绑定相册对话框（相册标题/ID 搜索选中 →
确认框携带 A22 文案「configVersion 将递增，官网无需改动」；清空即解绑）+
嵌入代码卡（{EMBED_ORIGIN}/embed/v1/loader.js + data-slot 令牌，一键复制；
EMBED_ORIGIN=VITE_EMBED_ORIGIN 缺省本机 viewer dev，.env.example 登记）。

- API 层 src/api/embedSlots.ts + types/api/embedSlot.d.ts（契约镜像）
- vitest 9 例：表单→载荷（缺省+夹取）、编辑载荷收敛、snippet 拼接、
  环境基址兜底、绑定变更分类、zh/en 键一致 + A22 短语断言
- Playwright e2e（真实 cn+ov 后端）：新建→绑定（gov-photos 直种 +
  seed-fixture 新增 sync-flush 模式经 bootstrap/真实发送管线投影 photos_ov）
  →嵌入代码卡含 token→ov 公开 feed 返回相册照片→换绑 configVersion+1 +
  feed 切换（A22）→停用 feed 404；admin playwright 配置补 ov webServer
- i18n zh/en（embedSlotsManage.* + menus.system.embedSlots）

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

apps/admin/src/locales/langs/zh.json

@@ -234,7 +234,8 @@
       "title": "账号与同步",
       "users": "账号管理",
       "userSync": "用户同步",
-      "usage": "用量统计"
+      "usage": "用量统计",
+      "embedSlots": "展示位管理"
     },
     "albums": {
       "title": "相册管理",
@@ -700,6 +701,87 @@
       "colCreatedAt": "记录时间"
     }
   },
+  "embedSlotsManage": {
+    "list": {
+      "title": "展示位管理（悬浮轮播组件挂载点）",
+      "create": "新建展示位",
+      "loadMore": "加载更多",
+      "noMore": "已全部加载",
+      "empty": "暂无展示位，点击「新建展示位」创建",
+      "loadFailed": "展示位列表加载失败",
+      "retry": "重试",
+      "colName": "名称",
+      "colAlbum": "绑定相册",
+      "colEnabled": "启用",
+      "colConfigVersion": "配置版本",
+      "colUpdatedAt": "更新时间",
+      "colActions": "操作",
+      "unbound": "未绑定",
+      "actionEdit": "编辑",
+      "actionBind": "绑定相册",
+      "actionCode": "嵌入代码"
+    },
+    "form": {
+      "nameLabel": "名称",
+      "namePlaceholder": "如：官网首页悬浮位",
+      "nameRequired": "请输入展示位名称",
+      "submit": "保存",
+      "positionLabel": "悬浮位置",
+      "positionLeft": "左侧",
+      "positionRight": "右侧",
+      "sizeLabel": "组件尺寸",
+      "sizeSm": "小（窄屏降级档）",
+      "sizeMd": "标准",
+      "intervalLabel": "轮播间隔",
+      "intervalUnit": "毫秒（3000-30000）",
+      "langLabel": "内容语言",
+      "langAuto": "跟随相册",
+      "langZh": "中文",
+      "langEn": "英文",
+      "collapsedLabel": "默认收起",
+      "collapsedHint": "初始仅展示小把手，点击展开"
+    },
+    "create": {
+      "title": "新建展示位",
+      "created": "展示位已创建（嵌入代码可在「嵌入代码」查看）"
+    },
+    "edit": {
+      "title": "编辑展示位",
+      "noChanges": "未修改任何内容",
+      "saved": "已保存（configVersion 已递增至 {version}）"
+    },
+    "bind": {
+      "title": "绑定相册：{name}",
+      "currentLabel": "当前绑定",
+      "targetLabel": "目标相册",
+      "searchPlaceholder": "输入相册标题或 ID 搜索",
+      "searching": "搜索中…",
+      "noMatch": "无匹配相册",
+      "clearHint": "清空选择并提交即解绑（公开端随即 404）",
+      "versionHint": "绑定变更仅递增 configVersion，已嵌入的官网无需改动（组件只认令牌）",
+      "confirmTitle": "确认绑定变更",
+      "confirmBind": "绑定相册后 configVersion 将递增，官网无需改动；组件将展示该相册的近期照片。",
+      "confirmRebind": "换绑相册后 configVersion 将递增，官网无需改动；组件将切换展示新相册的近期照片。",
+      "confirmUnbind": "解绑后 configVersion 将递增，官网无需改动；组件公开端将立即下线（404）。",
+      "actionBind": "绑定",
+      "actionRebind": "换绑",
+      "actionUnbind": "解绑",
+      "saved": "绑定已更新（configVersion 已递增至 {version}）"
+    },
+    "code": {
+      "title": "嵌入代码：{name}",
+      "tokenLabel": "展示位令牌（data-slot）",
+      "snippetLabel": "嵌入代码（粘贴到官网宿主页）",
+      "copy": "复制",
+      "copied": "已复制嵌入代码",
+      "hint": "将代码粘贴到官网页面即可挂载悬浮轮播；后续换绑相册、启停均无需改动该代码。",
+      "close": "关闭"
+    },
+    "toast": {
+      "enabledOn": "已启用（configVersion 已递增至 {version}）",
+      "enabledOff": "已停用（configVersion 已递增至 {version}，公开端随即 404）"
+    }
+  },
   "apiMsg": {
     "AUTH_INVALID_CREDENTIALS": "账号或密码错误",
     "AUTH_RATE_LIMITED": "登录失败次数过多，请稍后再试",