新增点击头像/昵称查看用户资料弹窗，接入消息气泡/@提及/群成员列表

新增全局 UserCardRoot（stores/userCard.ts 驱动，挂载在 AppShell 里，模式同
ConfirmDialogRoot），复用 getUserProfile 数据源，展示头像/昵称/性别地区/签名，
非本人时带发消息/语音/视频快捷操作，底部"查看完整资料"跳转到完整的
/contacts/{id} 页面。

接入点：
- MessageBubble.tsx：群聊和单聊的对方头像/昵称（原来只有群聊头像/昵称是
  Link 到完整资料页，单聊完全没有交互）
- drafty.tsx：@提及实体（Drafty.mention 的 uid 存在 ent[].data.val 里，
  之前渲染完全没读这个字段），"所有人"哨兵值除外
- GroupMembersModal.tsx / GroupDetailColumn.tsx：群成员列表的行内和紧凑
  头像格子

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

web/src/features/messages/MessageBubble.tsx

@@ -23,6 +23,7 @@ import { isFailedStatus, isSendingStatus, outgoingStatusLabel } from '@/lib/mess
 import { groupSenderLabel } from '@/lib/messages/sender-name';
 import { retryMessage } from '@/lib/tinode/send';
 import { ensureTopicAttached } from '@/lib/tinode/topics';
+import { openUserCard } from '@/stores/userCard';
 
 /** 设计稿 4.3：气泡上方角色标签，边框样式（不是填色）-- 群主 #ff951c、管理员 #1677ff，均不加背景。
  *  与 GroupMembersModal/GroupDetailColumn 里另外两种角色标签（填色 tag、圆角数字角标）故意不共用
@@ -173,10 +174,10 @@ export function MessageRow({
             relationship isn't a case this app has ever needed to support. Not during `selectMode`
             either -- the checkbox is the only thing a tap in this row should do while bulk-selecting,
             not navigate away and lose whatever's already been picked. */}
-        {isGroup && !mine && !selectMode && msg.from ? (
-          <Link to={`/contacts/${msg.from}`} className="flex-none no-underline">
-            <Avatar id={msg.from} name={groupSenderLabel(senderName)} avatarFileId={avatarFileId} className="h-9 w-9 rounded-lg text-sm" />
-          </Link>
+        {!mine && !selectMode && msg.from ? (
+          <button type="button" onClick={() => openUserCard(msg.from!)} className="flex-none">
+            <Avatar id={msg.from} name={isGroup ? groupSenderLabel(senderName) : peerName} avatarFileId={avatarFileId} className="h-9 w-9 rounded-lg text-sm" />
+          </button>
         ) : (
           <Avatar
             id={msg.from || (isGroup ? '' : peerName)}
@@ -190,9 +191,9 @@ export function MessageRow({
           {isGroup ? (
             <div className={`flex items-center gap-1 px-0.5 text-xs text-text-tertiary-4 ${mine ? 'flex-row-reverse' : ''}`}>
               {!mine && !selectMode && msg.from ? (
-                <Link to={`/contacts/${msg.from}`} className="text-text-tertiary-4 no-underline hover:underline">
+                <button type="button" onClick={() => openUserCard(msg.from!)} className="text-text-tertiary-4 hover:underline">
                   {groupSenderLabel(senderName)}
-                </Link>
+                </button>
               ) : (
                 <span>{mine ? '我' : groupSenderLabel(senderName)}</span>
               )}