群聊生命周期事件对被动成员实时不可见——前端兜底同步（真正的根因在后端，无法单靠前端代码彻底解决）

读im_be的server/im_group_events.go确认：群聊创建/加人/踢人/解散/转让群主等全部事件都走
publishIMGroupRealtimeEvent，这个函数只会广播给"当前已订阅该群topic的会话"——对比P2P场景专门
有一条deliverIMConversationSystemMessageToP2PSessions，会无视订阅状态强制投递给双方的session，
群聊从未做过同等实现。实机验证：一个全新创建、成员从未打开过的群，即使对方账号完全在线、页面就
停留在/messages上，群条目和未读角标都不会出现，等多久都不会自愈，必须手动刷新页面。

由于这个topic客户端本来就不知道存在，没有任何东西可以"响应"，前端无法真正修复，只能缓解：复用
subscribeMeTopic()/onReauthenticated()已经在用的withLaterSub()增量语义，改用getMeta()（不像
subscribe()那样在_attached为true时直接短路）定时（30秒）+ 切回标签页时主动拉一次"me"话题的最新
订阅列表。

实机验证：创建一个全新群、只邀请一个从未见过这个群的被动成员，在其页面保持被动、不做任何操作/
刷新的情况下——模拟切换标签页触发的focus/visibilitychange事件后约十几秒内，群条目正确出现在
列表顶部；另一次未受干预的测试中，纯靠30秒定时器本身也确认能自愈。

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

web/src/lib/tinode/topics.ts

@@ -355,3 +355,54 @@ onReauthenticated(() => {
     topic.subscribe(topic.startMetaQuery().withLaterData(1).build()).catch(() => {});
   }
 });
+
+const ME_RECONCILE_INTERVAL_MS = 30_000;
+let meReconcileTimer: ReturnType<typeof setInterval> | null = null;
+
+/**
+ * Best-effort mitigation for a real backend gap that no amount of frontend-only code can fully close:
+ * confirmed by reading im_be's server/im_group_events.go, EVERY group lifecycle event (created, member
+ * added/removed, dissolved, owner transferred, ...) goes through publishIMGroupRealtimeEvent, which
+ * only reaches sessions ALREADY subscribed to that specific group topic. Unlike P2P -- which has a
+ * dedicated force-delivery path straight to a peer's session regardless of subscription state
+ * (deliverIMConversationSystemMessageToP2PSessions) -- groups have no equivalent, so a member who has
+ * never opened a given group gets zero live signal when added to it: no chat-list row, no unread badge,
+ * nothing, indefinitely, until something re-syncs. Confirmed live (2026-09-16): a brand-new group with a
+ * genuinely passive, fully-connected, already-on-/messages member produced no change at all, even
+ * several seconds after a real message was sent into it.
+ *
+ * There is nothing to subscribe to or react to for a topic this client doesn't know exists yet, so the
+ * only thing a client can do is periodically ask "what's new" -- reusing the exact same incremental
+ * `withLaterSub()` semantics subscribeMeTopic()/onReauthenticated() above already rely on, just issued
+ * via `getMeta()` instead of `subscribe()`. `Topic.subscribe()` short-circuits once `_attached` is
+ * already true (the normal, undisturbed state this is guarding, unlike the reconnect case above), but
+ * `getMeta()` sends the `{get}` regardless of attach state -- the same distinction ConversationView's
+ * own P2P desc/presence fix relies on.
+ */
+function reconcileMeSubs() {
+  const me = getTinode().getMeTopic();
+  if (!me.isSubscribed()) return;
+  me.getMeta(me.startMetaQuery().withLaterSub().build()).catch(() => {});
+}
+
+/**
+ * Starts the periodic timer plus tab-focus/visibility triggers (the common "switched away and came
+ * back" case gets an immediate catch-up instead of waiting for the next tick). Call once per
+ * authenticated session (RequireAuth.tsx) and invoke the returned function on logout/unmount -- safe
+ * to start/stop repeatedly (React 19 StrictMode's mount->cleanup->remount included), unlike
+ * subscribeMeTopic() itself, which is guarded separately against being re-fired.
+ */
+export function startMeReconciliation(): () => void {
+  meReconcileTimer = setInterval(reconcileMeSubs, ME_RECONCILE_INTERVAL_MS);
+  const onVisible = () => {
+    if (document.visibilityState === 'visible') reconcileMeSubs();
+  };
+  document.addEventListener('visibilitychange', onVisible);
+  window.addEventListener('focus', reconcileMeSubs);
+  return () => {
+    if (meReconcileTimer) clearInterval(meReconcileTimer);
+    meReconcileTimer = null;
+    document.removeEventListener('visibilitychange', onVisible);
+    window.removeEventListener('focus', reconcileMeSubs);
+  };
+}