refactor(core): distinguish network errors from auth failures and refactor real-time messaging pipeline

- Add isNetworkError() helper and FetchCurrentUserResult discriminated union to prevent logout on network failures
- Refactor authService to return { kind: 'user' } | { kind: 'auth_failed' } | { kind: 'network_error' }
- Update authStore to preserve login state on network errors, only logout on auth failures
- Replace WSMessageHandler with RealtimeIngestionPipeline for improved real-time message handling
- Remove MessageDeduplication service; add store-level idempotent addOrReplaceMessage for message dedup
- Add atomic systemUnreadCount operations to prevent race conditions
- Add SearchHeader component for consistent search UI across screens
- Add 'home' TabBar variant with underline style matching HomeScreen
- Add Jest test infrastructure and exclude tests from tsconfig
- Fix ChatScreen history lock being stuck when scrolling to latest messages
- Remove unused call_participant_joined/left WS event types

src/screens/profile/FollowListScreen.tsx

@@ -5,7 +5,7 @@
  * 在宽屏下使用网格布局
  */
 
-import React, { useState, useEffect, useCallback, useMemo } from 'react';
+import React, { useState, useEffect, useCallback, useMemo, useRef } from 'react';
 import {
   View,
   FlatList,
@@ -22,6 +22,7 @@ import { User } from '../../types';
 import { useAuthStore, useUserStore } from '../../stores';
 import { authService } from '../../services';
 import { Avatar, Text, Button, Loading, EmptyState, ResponsiveContainer } from '../../components/common';
+import { SearchBar } from '../../components/business';
 import * as hrefs from '../../navigation/hrefs';
 import { useResponsive, useColumnCount } from '../../hooks';
 
@@ -53,9 +54,13 @@ const FollowListScreen: React.FC = () => {
   const [refreshing, setRefreshing] = useState(false);
   const [page, setPage] = useState(1);
   const [hasMore, setHasMore] = useState(true);
+  const [keyword, setKeyword] = useState('');
+  const [debouncedKeyword, setDebouncedKeyword] = useState('');
+  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   const isCurrentUser = currentUser?.id === userId;
   const title = type === 'following' ? '关注' : '粉丝';
+  const isSearching = debouncedKeyword.trim().length > 0;
 
   // 加载用户列表
   const loadUsers = useCallback(async (pageNum: number = 1, refresh: boolean = false) => {
@@ -64,11 +69,12 @@ const FollowListScreen: React.FC = () => {
     try {
       const pageSize = 20;
       let userList: User[] = [];
+      const trimmedKeyword = debouncedKeyword.trim();
       
       if (type === 'following') {
-        userList = await authService.getFollowingList(userId, pageNum, pageSize);
+        userList = await authService.getFollowingList(userId, pageNum, pageSize, trimmedKeyword);
       } else {
-        userList = await authService.getFollowersList(userId, pageNum, pageSize);
+        userList = await authService.getFollowersList(userId, pageNum, pageSize, trimmedKeyword);
       }
       
       if (refresh) {
@@ -84,12 +90,33 @@ const FollowListScreen: React.FC = () => {
     }
     setLoading(false);
     setRefreshing(false);
-  }, [userId, type, hasMore]);
+  }, [userId, type, hasMore, debouncedKeyword]);
 
-  // 初始加载
+  // 初始加载（包括 type/userId 切换以及防抖后关键词变化）
   useEffect(() => {
+    setLoading(true);
+    setHasMore(true);
     loadUsers(1, true);
-  }, [userId, type]);
+    // 仅在 userId/type/debouncedKeyword 变化时重新加载
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [userId, type, debouncedKeyword]);
+
+  // 关键词输入防抖（300ms）
+  useEffect(() => {
+    if (debounceRef.current) {
+      clearTimeout(debounceRef.current);
+    }
+    debounceRef.current = setTimeout(() => {
+      setDebouncedKeyword(keyword);
+    }, 300);
+
+    return () => {
+      if (debounceRef.current) {
+        clearTimeout(debounceRef.current);
+        debounceRef.current = null;
+      }
+    };
+  }, [keyword]);
 
   // 下拉刷新
   const onRefresh = useCallback(() => {
@@ -248,7 +275,18 @@ const FollowListScreen: React.FC = () => {
   // 渲染空状态
   const renderEmpty = () => {
     if (loading) return <Loading />;
-    
+
+    if (isSearching) {
+      return (
+        <EmptyState
+          title="没有找到匹配的用户"
+          description="换个关键词试试"
+          icon="account-search-outline"
+          variant="modern"
+        />
+      );
+    }
+
     const emptyText = type === 'following' 
       ? '还没有关注任何人' 
       : '还没有粉丝';
@@ -271,17 +309,34 @@ const FollowListScreen: React.FC = () => {
       <View style={styles.headerAccent} />
       <View style={styles.headerMainRow}>
         <Text variant="h2" style={styles.headerTitle}>{title}</Text>
-        <View style={styles.headerCountPill}>
-          <Text variant="caption" color={colors.text.secondary}>
-            共 {users.length}
-          </Text>
-        </View>
+        {!isSearching ? (
+          <View style={styles.headerCountPill}>
+            <Text variant="caption" color={colors.text.secondary}>
+              共 {users.length}
+            </Text>
+          </View>
+        ) : (
+          <View style={styles.headerCountPill}>
+            <Text variant="caption" color={colors.text.secondary}>
+              搜索结果
+            </Text>
+          </View>
+        )}
       </View>
       <Text variant="caption" color={colors.text.secondary} style={styles.headerSubtitle}>
         {type === 'following'
           ? (isCurrentUser ? '你已关注的用户' : 'TA关注的用户')
           : (isCurrentUser ? '关注你的用户' : 'TA的粉丝')}
       </Text>
+      <View style={styles.headerSearchWrap}>
+        <SearchBar
+          value={keyword}
+          onChangeText={setKeyword}
+          onSubmit={() => setDebouncedKeyword(keyword)}
+          placeholder={type === 'following' ? '搜索关注' : '搜索粉丝'}
+          compact
+        />
+      </View>
     </View>
   );
 
@@ -407,6 +462,9 @@ function createFollowListStyles(colors: AppColors) {
     headerSubtitle: {
       marginTop: spacing.xs,
     },
+    headerSearchWrap: {
+      marginTop: spacing.md,
+    },
     userItem: {
       flexDirection: 'row',
       alignItems: 'center',