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/views/tinode-web.jsx

@@ -2053,6 +2053,15 @@ class TinodeWeb extends React.Component {
   // (send-message.jsx) can gate on exactly the same real-world availability check as the existing
   // "..." menu items, instead of re-deriving (and risking drifting from) the same three conditions.
   canStartCall(topicName) {
+    // Never checked whether a call was already in progress -- the "..." menu entry and
+    // send-message.jsx's attachment-panel shortcut stayed clickable for the whole (very normal,
+    // product-supported) duration of a minimized call. A second click re-arms
+    // handleStartVideoCall/handleStartAudioCall's 60s ring timeout and forces callState back to
+    // CALL_STATE_OUTGOING_INITATED with no visible effect (the already-mounted CallPanel doesn't
+    // react to that prop), silently hanging up the real, healthy call a full minute later.
+    if (this.state.callState != CALL_STATE_NONE) {
+      return false;
+    }
     const topic = this.tinode.getTopic(topicName);
     if (!topic || topic._deleted || !Tinode.isP2PTopicName(topicName)) {
       return false;
@@ -2524,7 +2533,15 @@ class TinodeWeb extends React.Component {
       // arrives (or armCallRingTimeout's hang-up firing before it) leaves this call's callSeq
       // pointing at whatever the *previous* call's seq was, and the next outgoing call could read
       // that stale value for the brief window before its own ack lands.
-      callSeq: undefined
+      callSeq: undefined,
+      // handleCallAccept's "topic not subscribed yet" branch (below) sets this and waits for
+      // handleNewTopicCreated to both flip callState to CALL_STATE_IN_PROGRESS and clear this flag
+      // once that subscription succeeds -- but a call closed/abandoned (rejected, or the subscribe
+      // itself failing) before that ever happens left this stuck at true with no owner left to clear
+      // it. It would then get read by the *next*, entirely unrelated topic subscription that happens
+      // to succeed, incorrectly forcing callState to CALL_STATE_IN_PROGRESS for a call that was
+      // already given up on.
+      callShouldStart: false
     });
   }
 
@@ -2567,7 +2584,10 @@ class TinodeWeb extends React.Component {
             callTopic: null,
             callState: CALL_STATE_NONE,
             callSeq: null,
-            callAudioOnly: undefined
+            callAudioOnly: undefined,
+            // Same stuck-flag risk handleCallClose() guards against -- this call is being given up
+            // on here just as much as a local close/reject would, so it needs the same cleanup.
+            callShouldStart: false
           });
           return;
         }