feat(post): add post reference functionality with inline cards and suggestion search

Add support for referencing/quoting other posts within post content. Includes:
- New `post_ref` segment type with `PostRefSegmentData` interface for post references
- New `PostRefCard` component to display referenced posts inline
- Post suggestion search triggered by `#` in `PostMentionInput`
- Updated `PostContentRenderer` to render post reference segments
- Add `suggestPosts` and `recordRefClick` API methods in postService

Additional improvements:
- Add image gallery preview for user profile covers and avatars
- Make text selectable across CommentItem, PostContentRenderer, and PostDetailScreen
- Migrate FlatList to FlashList in PostDetailScreen and UserProfileScreen
- Add nestedScrollEnabled to CreatePostScreen
- Add clickable member avatars in GroupMembersScreen

src/components/business/PostMentionInput.tsx

@@ -8,7 +8,7 @@ import React, { useState, useEffect, useCallback, useRef } from 'react';
 import {
   View,
   TextInput,
-  FlatList,
+  ScrollView,
   TouchableOpacity,
   StyleSheet,
   Platform,
@@ -20,6 +20,7 @@ import Avatar from '../common/Avatar';
 import { useAppColors, spacing, fontSizes, borderRadius } from '../../theme';
 import { useAuthStore } from '../../stores';
 import { authService } from '../../services/auth';
+import { postService } from '../../services/post/postService';
 import { MessageSegment, AtSegmentData } from '../../types';
 
 interface MentionUser {
@@ -28,6 +29,14 @@ interface MentionUser {
   avatar: string | null;
 }
 
+interface SuggestPost {
+  id: string;
+  title: string;
+  channel?: string;
+}
+
+type SuggestionMode = 'none' | 'mention' | 'postref';
+
 interface PostMentionInputProps {
   value: string;
   onChangeText: (text: string) => void;
@@ -37,6 +46,7 @@ interface PostMentionInputProps {
   style?: any;
   minHeight?: number;
   autoExpand?: boolean;
+  onPostRefPasted?: (postId: string, title: string) => void;
 }
 
 const PostMentionInput: React.FC<PostMentionInputProps> = ({
@@ -48,14 +58,17 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
   style,
   minHeight = 100,
   autoExpand = false,
+  onPostRefPasted,
 }) => {
   const colors = useAppColors();
   const currentUser = useAuthStore(s => s.currentUser);
   const [followingUsers, setFollowingUsers] = useState<MentionUser[]>([]);
-  const [showMentions, setShowMentions] = useState(false);
+  const [suggestPosts, setSuggestPosts] = useState<SuggestPost[]>([]);
+  const [suggestionMode, setSuggestionMode] = useState<SuggestionMode>('none');
   const [mentionQuery, setMentionQuery] = useState('');
   const [mentionStartIndex, setMentionStartIndex] = useState(-1);
   const [loaded, setLoaded] = useState(false);
+  const [postSearchTimer, setPostSearchTimer] = useState<ReturnType<typeof setTimeout> | null>(null);
   const inputRef = useRef<TextInput>(null);
 
   useEffect(() => {
@@ -125,8 +138,42 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
       onChangeText(text);
 
       const cursorPos = text.length;
-      let atStart = -1;
 
+      // Check for # trigger (post ref search)
+      let hashStart = -1;
+      for (let i = cursorPos - 1; i >= 0; i--) {
+        if (text[i] === '#') {
+          hashStart = i;
+          break;
+        }
+        if (text[i] === ' ' || text[i] === '\n') {
+          break;
+        }
+      }
+
+      if (hashStart >= 0) {
+        const query = text.slice(hashStart + 1, cursorPos);
+        if (query.length >= 1 && !query.includes(' ') && !query.includes('\n')) {
+          if (postSearchTimer) {
+            clearTimeout(postSearchTimer);
+          }
+          const timer = setTimeout(async () => {
+            try {
+              const results = await postService.suggestPosts(query, 8);
+              setSuggestPosts(results);
+              setSuggestionMode('postref');
+              setMentionStartIndex(hashStart);
+            } catch {
+              // ignore
+            }
+          }, 300);
+          setPostSearchTimer(timer);
+          return;
+        }
+      }
+
+      // Check for @ trigger (mention)
+      let atStart = -1;
       for (let i = cursorPos - 1; i >= 0; i--) {
         if (text[i] === '@') {
           atStart = i;
@@ -142,15 +189,15 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
         if (!query.includes(' ') && !query.includes('\n')) {
           setMentionQuery(query);
           setMentionStartIndex(atStart);
-          setShowMentions(true);
+          setSuggestionMode('mention');
           return;
         }
       }
 
-      setShowMentions(false);
+      setSuggestionMode('none');
       rebuildSegments(text);
     },
-    [onChangeText, rebuildSegments]
+    [onChangeText, rebuildSegments, postSearchTimer],
   );
 
   const handleSelectMention = useCallback(
@@ -168,7 +215,7 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
       });
 
       onChangeText(newText);
-      setShowMentions(false);
+      setSuggestionMode('none');
       setMentionQuery('');
       setMentionStartIndex(-1);
 
@@ -176,7 +223,31 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
 
       inputRef.current?.focus();
     },
-    [value, mentionStartIndex, onChangeText, rebuildSegments]
+    [value, mentionStartIndex, onChangeText, rebuildSegments],
+  );
+
+  const handleSelectPost = useCallback(
+    (post: SuggestPost) => {
+      if (mentionStartIndex < 0) return;
+
+      const before = value.slice(0, mentionStartIndex);
+      const refText = `#${post.title} `;
+      const newText = before + refText;
+
+      onChangeText(newText);
+      setSuggestionMode('none');
+      setSuggestPosts([]);
+      setMentionStartIndex(-1);
+
+      if (onPostRefPasted) {
+        onPostRefPasted(post.id, post.title);
+      }
+
+      rebuildSegments(newText);
+
+      inputRef.current?.focus();
+    },
+    [value, mentionStartIndex, onChangeText, rebuildSegments, onPostRefPasted],
   );
 
   const renderMentionItem = ({ item }: { item: MentionUser }) => (
@@ -221,26 +292,66 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
         ]}
       />
 
-      {showMentions && filteredUsers.length > 0 && (
+      {suggestionMode === 'mention' && filteredUsers.length > 0 && (
         <View style={[styles.mentionPanel, { backgroundColor: colors.background.paper, borderColor: colors.divider }]}>
-          <FlatList
-            data={filteredUsers}
-            renderItem={renderMentionItem}
-            keyExtractor={item => item.id}
+          <ScrollView
             keyboardShouldPersistTaps="handled"
             nestedScrollEnabled
             style={styles.mentionList}
-          />
+          >
+            {filteredUsers.map(item => (
+              <React.Fragment key={item.id}>
+                {renderMentionItem({ item })}
+              </React.Fragment>
+            ))}
+          </ScrollView>
         </View>
       )}
 
-      {showMentions && filteredUsers.length === 0 && (
+      {suggestionMode === 'mention' && filteredUsers.length === 0 && (
         <View style={[styles.mentionPanel, { backgroundColor: colors.background.paper, borderColor: colors.divider }]}>
           <Text style={[styles.emptyText, { color: colors.text.hint }]}>
             没有找到匹配的关注用户
           </Text>
         </View>
       )}
+
+      {suggestionMode === 'postref' && suggestPosts.length > 0 && (
+        <View style={[styles.mentionPanel, { backgroundColor: colors.background.paper, borderColor: colors.divider }]}>
+          <ScrollView
+            keyboardShouldPersistTaps="handled"
+            nestedScrollEnabled
+            style={styles.mentionList}
+          >
+            {suggestPosts.map(item => (
+              <TouchableOpacity
+                key={item.id}
+                style={[styles.mentionItem, { borderBottomColor: colors.divider }]}
+                onPress={() => handleSelectPost(item)}
+                activeOpacity={0.7}
+              >
+                <MaterialCommunityIcons name="file-document-outline" size={18} color={colors.primary.main} />
+                <View style={styles.mentionInfo}>
+                  <Text style={[styles.mentionName, { color: colors.text.primary }]} numberOfLines={1}>
+                    {item.title}
+                  </Text>
+                  <Text style={[styles.mentionHint, { color: colors.text.hint }]}>
+                    点击引用帖子
+                  </Text>
+                </View>
+              </TouchableOpacity>
+            ))}
+          </ScrollView>
+        </View>
+      )}
+
+      {suggestionMode === 'postref' && suggestPosts.length === 0 && (
+        <View style={[styles.mentionPanel, { backgroundColor: colors.background.paper, borderColor: colors.divider }]}>
+          <Text style={[styles.emptyText, { color: colors.text.hint }]}>
+            没有找到匹配的帖子
+          </Text>
+        </View>
+      )}
     </View>
   );
 };