refactor: migrate post operations to use case architecture with differential updates

Migrate post-related operations from direct service/store calls to a new use case architecture featuring differential updates. Key changes include: (1) introduce ProcessPostUseCase to handle like, unlike, favorite, unfavorite, delete, and fetch operations with proper state management, (2) add useDifferentialPosts hook for efficient list rendering with minimal re-renders, (3) add PostDiffCalculator and PostUpdateBatcher in infrastructure layer for incremental updates, (4) deprecate NotificationItem component in favor of SystemMessageItem, (5) remove deprecated interactive methods from userStore, (6) add posts_cache table to local datasource, (7) clean up legacy MessageDTO and ConversationDTO types, (8) remove deprecated hook useBreakpointCheck, (9) refactor MessageBubble to use measureInWindow directly for better React Native compatibility

src/core/entities/Post.ts

@@ -0,0 +1,267 @@
+/**
+ * Post Entity - 帖子领域实体
+ * 定义帖子的核心属性和行为，不依赖任何外部框架
+ */
+
+// ==================== 帖子状态枚举 ====================
+
+export type PostStatus = 'published' | 'draft' | 'deleted';
+
+// ==================== 值对象 ====================
+
+/**
+ * 帖子作者信息
+ */
+export interface PostAuthor {
+  id: string;
+  username: string;
+  nickname?: string;
+  avatar?: string;
+}
+
+/**
+ * 帖子图片信息
+ */
+export interface PostImage {
+  url: string;
+  width?: number;
+  height?: number;
+  thumbnailUrl?: string;
+}
+
+/**
+ * 帖子标签
+ */
+export interface PostTag {
+  id: string;
+  name: string;
+}
+
+// ==================== 主实体 ====================
+
+/**
+ * 帖子实体
+ */
+export interface Post {
+  /** 帖子唯一标识 */
+  id: string;
+  /** 作者ID */
+  authorId: string;
+  /** 作者信息 */
+  author?: PostAuthor;
+  /** 帖子标题 */
+  title: string;
+  /** 帖子内容 */
+  content: string;
+  /** 图片列表 */
+  images: PostImage[];
+  /** 点赞数 (camelCase) */
+  likesCount: number;
+  /** 评论数 (camelCase) */
+  commentsCount: number;
+  /** 分享数 (camelCase) */
+  sharesCount: number;
+  /** 浏览数 (camelCase) */
+  viewsCount: number;
+  /** 收藏数 (camelCase) */
+  favoritesCount: number;
+  /** 当前用户是否已点赞 (camelCase) */
+  isLiked: boolean;
+  /** 当前用户是否已收藏 (camelCase) */
+  isFavorited: boolean;
+  /** 是否置顶 (camelCase) */
+  isPinned: boolean;
+  /** 帖子状态 */
+  status: PostStatus;
+  /** 所属社区ID */
+  communityId?: string;
+  /** 标签列表 */
+  tags: string[];
+  /** 创建时间 */
+  createdAt: string;
+  /** 更新时间 */
+  updatedAt: string;
+  
+  // ==================== 向后兼容字段 (snake_case) ====================
+  // 这些字段用于与旧代码兼容，新代码应使用 camelCase 版本
+  
+  /** @deprecated 请使用 likesCount */
+  likes_count?: number;
+  /** @deprecated 请使用 commentsCount */
+  comments_count?: number;
+  /** @deprecated 请使用 favoritesCount */
+  favorites_count?: number;
+  /** @deprecated 请使用 sharesCount */
+  shares_count?: number;
+  /** @deprecated 请使用 viewsCount */
+  views_count?: number;
+  /** @deprecated 请使用 isLiked */
+  is_liked?: boolean;
+  /** @deprecated 请使用 isFavorited */
+  is_favorited?: boolean;
+  /** @deprecated 请使用 isPinned */
+  is_pinned?: boolean;
+  /** @deprecated 请使用 authorId */
+  user_id?: string;
+  /** @deprecated 请使用 createdAt */
+  created_at?: string;
+  /** @deprecated 请使用 updatedAt */
+  updated_at?: string;
+  /** @deprecated 请使用 communityId */
+  community_id?: string;
+  /** @deprecated 请使用 status */
+  status_str?: string;
+  /** 投票帖子标识 (部分旧代码使用) */
+  is_vote?: boolean;
+  /** 锁定状态 (部分旧代码使用) */
+  is_locked?: boolean;
+  /** 置顶评论 (部分旧代码使用) */
+  top_comment?: any;
+}
+
+// ==================== 工厂函数 ====================
+
+/**
+ * 创建帖子作者信息
+ */
+export const createPostAuthor = (data: Partial<PostAuthor>): PostAuthor => ({
+  id: data.id || '',
+  username: data.username || '',
+  nickname: data.nickname,
+  avatar: data.avatar,
+});
+
+/**
+ * 创建帖子图片信息
+ */
+export const createPostImage = (data: Partial<PostImage>): PostImage => ({
+  url: data.url || '',
+  width: data.width,
+  height: data.height,
+  thumbnailUrl: data.thumbnailUrl,
+});
+
+/**
+ * 创建帖子实体
+ */
+export const createPost = (data: Partial<Post>): Post => ({
+  id: data.id || '',
+  authorId: data.authorId || '',
+  author: data.author,
+  title: data.title || '',
+  content: data.content || '',
+  images: data.images || [],
+  likesCount: data.likesCount || 0,
+  commentsCount: data.commentsCount || 0,
+  sharesCount: data.sharesCount || 0,
+  viewsCount: data.viewsCount || 0,
+  favoritesCount: data.favoritesCount || 0,
+  isLiked: data.isLiked || false,
+  isFavorited: data.isFavorited || false,
+  isPinned: data.isPinned || false,
+  status: data.status || 'published',
+  communityId: data.communityId,
+  tags: data.tags || [],
+  createdAt: data.createdAt || new Date().toISOString(),
+  updatedAt: data.updatedAt || new Date().toISOString(),
+});
+
+// ==================== 类型守卫 ====================
+
+/**
+ * 检查是否为有效的帖子状态
+ */
+export const isValidPostStatus = (status: string): status is PostStatus => {
+  return ['published', 'draft', 'deleted'].includes(status);
+};
+
+/**
+ * 检查帖子是否已发布
+ */
+export const isPostPublished = (post: Post): boolean => {
+  return post.status === 'published';
+};
+
+/**
+ * 检查帖子是否已删除
+ */
+export const isPostDeleted = (post: Post): boolean => {
+  return post.status === 'deleted';
+};
+
+/**
+ * 检查帖子是否为草稿
+ */
+export const isPostDraft = (post: Post): boolean => {
+  return post.status === 'draft';
+};
+
+// ==================== 辅助函数 ====================
+
+/**
+ * 检查当前用户是否为帖子作者
+ */
+export const isPostAuthor = (post: Post, userId: string): boolean => {
+  return post.authorId === userId;
+};
+
+/**
+ * 获取帖子的主要图片（第一张图片）
+ */
+export const getPostThumbnail = (post: Post): PostImage | undefined => {
+  return post.images[0];
+};
+
+/**
+ * 检查帖子是否包含图片
+ */
+export const hasPostImages = (post: Post): boolean => {
+  return post.images.length > 0;
+};
+
+/**
+ * 获取帖子的显示标题（优先使用标题，否则使用内容摘要）
+ */
+export const getPostDisplayTitle = (post: Post, maxLength: number = 50): string => {
+  if (post.title) {
+    return post.title;
+  }
+  if (post.content.length > maxLength) {
+    return post.content.substring(0, maxLength) + '...';
+  }
+  return post.content;
+};
+
+/**
+ * 计算帖子的互动总数
+ */
+export const getPostTotalEngagement = (post: Post): number => {
+  return post.likesCount + post.commentsCount + post.sharesCount + post.favoritesCount;
+};
+
+/**
+ * 格式化帖子创建时间为相对时间描述
+ */
+export const formatPostTime = (post: Post): string => {
+  const createdAt = new Date(post.createdAt);
+  const now = new Date();
+  const diffMs = now.getTime() - createdAt.getTime();
+  const diffSeconds = Math.floor(diffMs / 1000);
+  const diffMinutes = Math.floor(diffSeconds / 60);
+  const diffHours = Math.floor(diffMinutes / 60);
+  const diffDays = Math.floor(diffHours / 24);
+
+  if (diffSeconds < 60) {
+    return '刚刚';
+  }
+  if (diffMinutes < 60) {
+    return `${diffMinutes}分钟前`;
+  }
+  if (diffHours < 24) {
+    return `${diffHours}小时前`;
+  }
+  if (diffDays < 7) {
+    return `${diffDays}天前`;
+  }
+  return createdAt.toLocaleDateString('zh-CN');
+};