修复群聊自己发消息后聊天列表出现虚假未读红点

reconcileMeSubs() 的周期性 me.getMeta(withLaterSub()) 拉取，对已知会话原有的
回归保护(seq<=prev.seq && unread>prev.unread) 只防得住"seq没变但unread变大"
这一种情形。自己在已打开的会话里发消息时：本地 confirmedReadSeq 会同步立即
更新（早于服务端），但发给服务端的 note read 是异步的；如果这次拉取的请求
恰好在发送前就已经在途，返回时 seq 已经真实前进(不满足 seq<=prev.seq)、
read 却还没追上，旧保护不生效，虚假的 unread 就被原样套用——哪怕这条消息
就是自己刚发的。

补一个独立的、无条件的兜底：用已有的 confirmedReadSeq 记录做下限，read 永远
不会被这次拉取拉回到低于"本客户端已确认看过的位置"，与原有保护并存、不冲突。

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

web/src/lib/tinode/topics.ts

@@ -750,6 +750,24 @@ function reconcileMeSubs() {
           c.unread = prev.unread;
           notifyTopic(c.topic);
         }
+        // Separate, real bug this same guard doesn't cover (live-confirmed 2026-09-24, reported
+        // directly): sending your OWN message into a topic that's already open bumps `confirmedReadSeq`
+        // synchronously (ConversationView's noteRead effect), long before the async `{note read}` this
+        // relies on has actually reached the server. A `{get}` already in flight since before that
+        // moment can come back with a real, ADVANCED `seq` (the new message the server just accepted)
+        // paired with a `read` that hasn't caught up server-side yet -- `seq <= prev.seq` above is
+        // false (seq genuinely changed), so that guard correctly doesn't fire, and this spurious
+        // `unread:1` gets applied verbatim even though the user is the one who just sent it. Clamp
+        // `read` to what THIS client already knows it has confirmed seeing, regardless of what the
+        // fetch says -- a floor, never pushes `read` past the server's own value when the server is
+        // genuinely ahead of this record (e.g. read from a different, already-synced device).
+        const confirmed = confirmedReadSeq.get(c.topic) || 0;
+        if (confirmed > (c.read || 0)) {
+          c.read = confirmed;
+          if ((c.recv || 0) < confirmed) c.recv = confirmed;
+          c.unread = Math.max(0, (c.seq || 0) - confirmed);
+          notifyTopic(c.topic);
+        }
       }
     })
     .catch(() => {});