第七轮深度测试：修复7个agent发现的12处前端问题，重点是列表分页截断与呼叫/播放状态机

- 通话状态机（Ch8）：canStartCall 补齐通话中重复发起的防护，callShouldStart 补齐放弃/失败路径的清理
- 分页截断（Ch5-6）：新增 fetchAllPages 辅助函数，修复通讯录/黑名单/好友申请/群成员/管理员/禁言等
  11 处列表只读首页导致真实成员被遗漏的问题；群角色判断改用不受分页影响的 getGroup().my_role
- 消息与媒体（Ch3-4/Ch7/Ch9）：录音超时污染时长、手动重试丢失 head 导致消息被错误分类、批量删除
  未取消上传中附件、语音播放器补齐同时只能播一条、workplace-collaboration-view 冗余重试请求
- 独立密码/青少年模式（Ch10-11）：设置密码后按调用来源判断是否应自动开启青少年模式，避免关闭流程
  中途"忘记密码"被误当成开启；注销账号确认文案补充群主后果说明

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/lib/im-api.js

@@ -181,6 +181,27 @@ export function translateReason(reason, details) {
 
 const idem = () => ({'Idempotency-Key': requestId()});
 
+// Most list endpoints here cap out at 20-50 items per page (some as low as 30, e.g. group
+// members against a 128-member cap) and round7 testing found several call sites only ever
+// fetched the first page -- for things like "am I this group's owner/admin" or the admin
+// candidate list, a real owner/admin sitting past page 1 went undetected entirely rather than
+// just showing an incomplete list. Empty/repeated next_cursor means done; this app's list
+// responses haven't been observed to send a separate has_more that disagrees with that.
+export async function fetchAllPages(fetchPage, startCursor = '') {
+  let cursor = startCursor;
+  let items = [];
+  for (;;) {
+    const page = await fetchPage(cursor);
+    items = items.concat((page && page.items) || []);
+    const nextCursor = (page && page.next_cursor) || '';
+    if (!nextCursor || nextCursor === cursor) {
+      break;
+    }
+    cursor = nextCursor;
+  }
+  return items;
+}
+
 export const imGet = (path, opts) => imRequest(path, opts);
 export const imPost = (path, body, opts = {}) => imRequest(path, {method: 'POST', body, headers: idem(), ...opts});
 export const imPatch = (path, body, opts = {}) => imRequest(path, {method: 'PATCH', body, headers: idem(), ...opts});