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/types/dto.ts

@@ -150,7 +150,7 @@ export type MessageStatus = 'normal' | 'recalled' | 'deleted';
 // ==================== Message Segment Types ====================
 
 // Segment类型
-export type SegmentType = 'text' | 'image' | 'voice' | 'video' | 'file' | 'at' | 'reply' | 'face' | 'link' | 'vote';
+export type SegmentType = 'text' | 'image' | 'voice' | 'video' | 'file' | 'at' | 'reply' | 'face' | 'link' | 'vote' | 'post_ref';
 
 // 文本Segment数据
 export interface TextSegmentData {
@@ -232,6 +232,20 @@ export interface VoteSegmentData {
   is_multi_choice?: boolean;
 }
 
+// 帖子内链Segment数据
+export interface PostRefSegmentData {
+  post_id: string;
+  title?: string;
+  author?: {
+    id: string;
+    nickname: string;
+    avatar?: string;
+  };
+  status?: string;
+  accessible?: boolean;
+  click_count?: number;
+}
+
 // MessageSegment 联合类型 - 使用 discriminated union
 export type MessageSegment =
   | { type: 'text'; data: TextSegmentData }
@@ -243,7 +257,8 @@ export type MessageSegment =
   | { type: 'reply'; data: ReplySegmentData }
   | { type: 'face'; data: FaceSegmentData }
   | { type: 'link'; data: LinkSegmentData }
-  | { type: 'vote'; data: VoteSegmentData };
+  | { type: 'vote'; data: VoteSegmentData }
+  | { type: 'post_ref'; data: PostRefSegmentData };
 
 // 消息响应
 export interface MessageResponse {
@@ -787,6 +802,10 @@ export function extractTextFromSegments(segments?: MessageSegment[], memberMap?:
       case 'reply':
         // 回复不显示在预览中
         break;
+      case 'post_ref':
+        const refData = segment.data as PostRefSegmentData;
+        result += refData.title ? `[帖子: ${refData.title}]` : '[帖子引用]';
+        break;
     }
   }
 
@@ -967,6 +986,10 @@ export async function extractTextFromSegmentsAsync(
       case 'reply':
         // 回复不显示在预览中
         break;
+      case 'post_ref':
+        const refDataAsync = segment.data as PostRefSegmentData;
+        result += refDataAsync.title ? `[帖子: ${refDataAsync.title}]` : '[帖子引用]';
+        break;
     }
   }