修复P2P会话完全不出现在聊天列表、标题栏显示原始ID+离线的根因

根因：tinode-sdk自带的Topic.topicType()前缀表只认'usr'为P2P类型前缀，没有
'p2p'这个条目，而本后端真实分配的P2P话题名是`p2p<hash>`形式——导致
isCommType()对每一个P2P会话都恒定返回false，MeTopic.contacts()因此把所有
单聊会话过滤掉。用真实账号实测确认这不是新会话/顶号账号特有的问题：任何
账号的任何P2P好友关系都受影响，只是群聊和"slf"自聊天不受影响所以此前一直
没被发现。

聊天列表改用Tinode#mapTopics()（不做类型过滤的原始遍历）+ 本项目自己正确
的前缀判断（p2p/grp/slf），不再依赖SDK自身的isCommType()。

实测（e2etester1/e2etester2真实新建好友关系，此前从未聊过天）：修复前
标题栏显示原始topic hash+"离线"（对方实际在线）、侧边栏"暂无会话"（消息
其实已正确送达，只是不可见）；修复后标题栏正确显示对方昵称+"在线"，侧边栏
正确出现该会话及消息预览。

web/src/lib/tinode/tinode-sdk.d.ts

@@ -302,6 +302,10 @@ declare module 'tinode-sdk' {
 
     getMeTopic(): MeTopic;
     getTopic(topicName: string): Topic;
+    /** Iterates EVERY locally-cached topic (any type, including `me`/`fnd`), unlike `MeTopic.contacts()`
+     *  which additionally filters by `isCommType()` -- see topics.ts's `getChatListSnapshot` for why
+     *  that filter can't be trusted for this backend's P2P topics. */
+    mapTopics(callback: (topic: Topic, key: string) => void): void;
 
     account(userId: string, scheme: string, secret: string, login: boolean, desc?: unknown): Promise<unknown>;
     createAccountBasic(

web/src/lib/tinode/topics.ts

@@ -253,22 +253,50 @@ export function ensureTopicAttached(topicName: string): Promise<Topic> {
 
 let chatListSnapshot: Contact[] | null = null;
 
+/**
+ * Real, addressable chat-list topic types this backend actually issues -- deliberately NOT using
+ * `Topic#isCommType()`/`isP2PType()` (confirmed live by reading tinode-sdk's own `Topic.topicType()`
+ * table: it maps prefix `'usr'` to P2P, with NO entry for `'p2p'` at all). That table is right for a
+ * peer ALIAS (`usr<peerId>`, used before a P2P topic has ever been subscribed), but this backend's
+ * REAL, server-assigned P2P topic name is `p2p<hash>` (confirmed via raw `{meta topic:"me"}` capture:
+ * every subscription the server reports uses this form, never the alias) -- so `isCommType()` returns
+ * false for every P2P topic once its real name is known, silently filtering ALL of them out of
+ * `MeTopic.contacts()`. This has nothing to do with account age or how a conversation was opened --
+ * verified by direct fresh-login inspection that even a heavily-used account with many real, working
+ * P2P friendships had ZERO P2P entries in `contacts()`; every P2P row the chat list has ever shown
+ * this session was actually the special-cased `slf` self-chat entry.
+ */
+function isChatListTopicName(name: string): boolean {
+  return name.startsWith('p2p') || name.startsWith('grp') || name === 'slf';
+}
+
 /**
  * Cached the same way getMessagesSnapshot is, but invalidated by ANY topic's change (a new message
  * on a contact that isn't currently open still needs to move that row and refresh its preview).
  * Triggers each contact's one-shot preview prefetch as a side effect of being read -- cheap and
  * idempotent (prefetchPreview no-ops after the first call per topic), so it's fine to do this on
  * every rebuild rather than needing a separate "wire up previews" pass.
+ *
+ * Uses `Tinode#mapTopics` (every locally-cached topic, unfiltered) + `isChatListTopicName` instead of
+ * `MeTopic#contacts()` -- see that function's own comment for why `contacts()`'s built-in filter can't
+ * be trusted here. `mapTopics` still only sees topics the SDK has locally cached, which `me`'s own
+ * subscribe (`subscribeMeTopic`'s `withLaterSub()`) and any direct `openConversation()` both populate.
  */
 export function getChatListSnapshot(): Contact[] {
   if (chatListSnapshot) return chatListSnapshot;
   const byTopic = new Map<string, Contact>();
-  getTinode()
-    .getMeTopic()
-    .contacts((contact) => {
-      if (!contact.topic) return;
-      prefetchPreview(contact.topic);
-      byTopic.set(contact.topic, contact);
+  getTinode().mapTopics((topic) => {
+    if (!topic.name || !isChatListTopicName(topic.name)) return;
+    prefetchPreview(topic.name);
+    // `.topic` (what every consumer of this list actually reads) normally arrives via
+    // `_processMetaSubs` merging the server's own `sub.topic` field onto this same cached instance --
+    // but a brand-new P2P topic reached through `openConversation()` is cached here the moment its
+    // OWN subscribe resolves, potentially before `me`'s subscription list has ever reported it. Set
+    // explicitly rather than assuming that merge already happened; kept as the same live instance
+    // (not a clone) so prototype methods like `latestMessage()` survive.
+    const contact = topic as unknown as Contact;
+    contact.topic = topic.name;
+    byTopic.set(topic.name, contact);
   });
   const rows = [...byTopic.values()];
   chatListSnapshot = rows;