fix(web): 隐藏文件助手入口，修复自聊天详情栏错误操作

后端目前没有支持文件助手所需的配额/分类等能力，只是把它当作
普通话题处理；与其做一个功能不全的界面，先从导航栏、会话列表
置顶区、通讯录固定入口、设置页移动端快捷入口中移除该入口。slf
话题现在按普通会话行为处理（排序、未读计数均不再特殊处理）。

同时修复 DetailColumn 对自聊天（slf）显示语音/视频通话、备注、
拉黑、举报、删除好友等对自己无意义操作的问题，改为仅显示适用
的发消息/查找聊天记录/置顶/免打扰/清空聊天记录等项。

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

web/src/features/messages/ChatListColumn.tsx

@@ -15,17 +15,22 @@ import { useChatList, useTinode } from '@/lib/tinode/hooks';
 import { useSessionStore } from '@/stores/session';
 
 /**
- * README §2.1's two always-pinned utility rows. Real, confirmed backend facts (docs/IM-前后端对接
- * 文档.md:909): topic names are fixed ("slf"/"sys"), but 系统消息's unread comes from a separate
+ * README §2.1's always-pinned utility row. Real, confirmed backend fact (docs/IM-前后端对接
+ * 文档.md:909): topic name is fixed ("sys"), but 系统消息's unread comes from a separate
  * notifications table (not the topic itself). `/messages/system` renders a real dedicated timeline
  * (SystemMessagesView, off `GET /v1/im/system-notifications`) -- nested under MessagesLayout like
  * every `:topicId` conversation, not a standalone top-level route, so the chat list column stays
  * docked next to it (a user report caught the list vanishing when this was still `/chat/system`,
- * a route outside MessagesLayout entirely). `/files` redirects into a real
- * ConversationView on the `slf` topic instead -- README §9.2's own dedicated 3-column file browser
- * (categories, storage quota, upload progress) has no backing REST API at all (confirmed via a
- * research pass), so a plain conversation view is the honest choice over a quota card with invented
- * numbers.
+ * a route outside MessagesLayout entirely).
+ *
+ * 文件助手 (a pinned entry that redirected into a plain ConversationView on the `slf` topic --
+ * README §9.2's own dedicated 3-column file browser has no backing REST API at all, confirmed via a
+ * research pass) was deliberately removed from here: the user found it confusing -- it's really
+ * just a chat thread with yourself wearing a folder icon, and DetailColumn's friend-only actions
+ * (拉黑/举报/删除好友) made no sense pointed at yourself. Hidden across every entry point (NavRail,
+ * here, ContactsListColumn, SettingsLayout's mobile shortcuts) rather than half-built into a real
+ * file browser the backend can't support yet. `slf` itself is untouched -- if it ever has real
+ * message history it still surfaces as an perfectly ordinary contact row, sorted like any other.
  */
 const PINNED_ENTRIES = [
   {
@@ -36,14 +41,6 @@ const PINNED_ENTRIES = [
     route: '/messages/system',
     colorClass: 'bg-warn-bg text-warn',
   },
-  {
-    key: 'file_assistant' as const,
-    badgeKey: 'file_assistant_unread_count' as const,
-    label: '文件助手',
-    icon: 'folder',
-    route: '/files',
-    colorClass: 'bg-success-bg text-success',
-  },
 ];
 
 /** Chat-list row sort: 置顶 (README §2.1's "置顶 > 最近") first, then by `touched` (last activity)
@@ -68,14 +65,7 @@ export function ChatListColumn() {
   const memberCountByTopic = new Map(groupsQuery.data?.map((g) => [g.topic, g.member_count]));
   const [query, setQuery] = useState('');
   const [creatingGroup, setCreatingGroup] = useState(false);
-  // `slf` (self-chat) is permanently represented by the pinned 文件助手 entry above (see
-  // PINNED_ENTRIES's own doc comment) -- it also comes back as an ordinary contact once it has any
-  // real message history (e.g. the very first time something gets sent through 文件助手), which
-  // without this filter renders it a SECOND time as its own chronologically-sorted row further down.
-  // Confirmed live: with both rows present, navigating to /messages/slf (via either one) satisfies
-  // both rows' own "am I the active one" check at once, highlighting them simultaneously -- a real,
-  // reproducible duplicate-representation bug, not just a cosmetic double-highlight.
-  const sorted = [...contacts].filter((c) => c.topic !== 'slf').sort((a, b) => {
+  const sorted = [...contacts].sort((a, b) => {
     const pinDelta = (b.private?.pinned ? 1 : 0) - (a.private?.pinned ? 1 : 0);
     return pinDelta || (b.touched?.getTime() ?? 0) - (a.touched?.getTime() ?? 0);
   });
@@ -105,10 +95,7 @@ export function ChatListColumn() {
       <div className="flex flex-1 flex-col overflow-y-auto">
         {pinned.map((entry) => {
           const unread = bootstrap.data?.entry_badges?.[entry.badgeKey] || 0;
-          // `/files` redirects to `/messages/slf`, so its "currently open" check is keyed off the
-          // resulting topicId rather than the route it navigates from, unlike `/messages/system`
-          // which is the real, final path.
-          const active = entry.route === '/files' ? topicId === 'slf' : location.pathname === entry.route;
+          const active = location.pathname === entry.route;
           return (
             <Link
               key={entry.key}