feat(mobile): UI-03 forms and collaboration pages (09-12)

- Page 09 create: grouped form (Event details / Description & languages),
  required default-language selector, zh-CN/en tabs with per-locale
  title/description/venue/address, explicit timezone field, bottom save
  button kept keyboard-reachable, create mode has no Access tab
- Page 10 edit: Details/Access tabs sharing one draft; Access has four
  switches with explanations; original downloads constrained by downloads
  (disabled + forced off in PATCH); unsaved-changes PopScope confirm;
  save commits all changes in one minimal PATCH
- Page 11 members: Owner group + Collaborators list with initial avatars
  and per-row remove; full-width Invite colleague opens account-search
  bottom sheet (debounced prefix search, race guard, already-added state);
  remove confirm names the member
- Page 12 categories: extracted to standalone page with per-row edit/
  delete menu and New category sheet (language tabs + name + sort order);
  delete confirm mentions photo impact; collaborator browse-only; old
  inline section removed from album detail
- l10n: new form/members/categories keys both locales; regenerated
- tests: form 14, members 6, categories 7, detail nav 1; full suite green

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

apps/mobile/lib/l10n/app_zh.arb

@@ -66,28 +66,40 @@
   "albumsEmpty": "暂无相册，点击「新建相册」开始",
   "loadMoreFailed": "加载更多失败，点击重试",
   "albumCreate": "新建相册",
-  "albumEdit": "编辑相册",
-  "albumSectionEventInfo": "活动信息",
-  "albumSectionContent": "多语言内容",
-  "albumSectionAccess": "访问设置",
   "albumTitle": "标题",
   "albumDescription": "描述",
   "albumVenue": "场地",
   "albumAddress": "地址",
-  "albumDefaultLocale": "默认语言",
   "albumStartAt": "开始时间",
   "albumEndAtOptional": "结束时间（可选）",
   "clearEndAt": "清除结束时间",
   "albumTimezone": "时区",
   "albumTimezoneInvalid": "无效的 IANA 时区名称",
-  "switchUpload": "允许上传",
-  "switchPublic": "公开可见",
-  "switchDownload": "允许下载",
-  "switchOriginalDownload": "允许下载原图",
   "formStartAtRequired": "请选择开始时间",
   "formDefaultLocaleMissing": "默认语言必须填写标题",
   "formTitleRequiredWithFields": "填写了描述/场地/地址时，标题不能为空",
   "formEndAtNotAfterStartAt": "结束时间必须晚于开始时间",
+  "formEventDetails": "活动信息",
+  "formDescriptionLanguages": "描述与语言",
+  "formDefaultLanguage": "默认语言",
+  "formDetailsTab": "详情",
+  "formAccessTab": "访问",
+  "formAllowUploads": "允许上传",
+  "formAllowUploadsDesc": "允许工作人员向该相册上传照片",
+  "formPublicAccess": "公开访问",
+  "formPublicAccessDesc": "任何获得链接的人都可以查看照片",
+  "formAllowDownloads": "允许下载",
+  "formAllowDownloadsDesc": "观众可以下载浏览质量的照片",
+  "formOriginalDownloads": "下载原图",
+  "formOriginalDownloadsDesc": "观众可以下载原图照片",
+  "createAlbumTitle": "新建相册",
+  "createAlbumSubmit": "新建相册",
+  "editAlbumTitle": "编辑相册",
+  "saveChanges": "保存修改",
+  "unsavedChangesTitle": "放弃修改？",
+  "unsavedChangesBody": "修改尚未保存，离开将丢失这些修改。",
+  "discardChanges": "放弃",
+  "keepEditing": "继续编辑",
   "create": "创建",
   "save": "保存",
   "albumStatusActive": "正常",
@@ -98,27 +110,36 @@
   "tagOriginal": "原图",
   "notSet": "未定",
   "actionEdit": "编辑",
-  "albumMembers": "成员管理",
+  "membersTitle": "成员",
+  "membersTitleCount": "成员（{count}）",
+  "@membersTitleCount": { "placeholders": { "count": { "type": "int" } } },
+  "ownerGroup": "创建者",
+  "collaboratorsGroup": "协作者",
+  "noCollaborators": "还没有协作者",
+  "inviteColleague": "邀请同事",
+  "alreadyAdded": "已添加",
+  "add": "添加",
+  "categoriesTitle": "分类",
+  "newCategory": "新增分类",
+  "editCategory": "编辑分类",
+  "deleteCategoryConfirm": "删除「{name}」？该分类下的照片将变为未分类。",
+  "@deleteCategoryConfirm": { "placeholders": { "name": { "type": "String" } } },
+  "noCategories": "暂无分类",
   "albumCategories": "分类管理",
   "shareQrTitle": "分享二维码",
   "albumPhotos": "照片管理",
   "delete": "删除",
-  "deleteConfirmCategory": "确定删除该分类？该分类下的照片将变为未分类。",
-  "categoryEmpty": "暂无分类，点击右上角新增",
-  "categoryAdd": "新增分类",
-  "categoryEdit": "编辑分类",
   "categoryNameZh": "中文名称",
   "categoryNameEn": "英文名称",
   "categorySortOrder": "排序序号",
   "categoryNameRequired": "至少填写一个语言的名称",
   "categorySortOrderInvalid": "排序序号必须是整数",
-  "albumMembersEmpty": "暂无成员",
   "inviteSearchHint": "输入账号前缀搜索邀请（至少 2 个字符）",
   "inviteNoResults": "未找到匹配用户",
-  "invite": "邀请",
   "memberInvited": "已邀请",
   "removeMember": "移除成员",
-  "removeMemberConfirm": "确定移除该成员？",
+  "removeMemberConfirm": "确定将 {name} 从该相册移除？",
+  "@removeMemberConfirm": { "placeholders": { "name": { "type": "String" } } },
   "roleOwner": "创建者",
   "roleCollaborator": "协作者",
   "selfMarker": "（我）",