refactor(stores): unify data sources pattern and extract BaseManager base class

- Add BaseManager/CachedManager base classes to eliminate duplicate cache logic
- Add postListSources.ts with IPostListPagedSource interface
- Add groupListSources.ts with IGroupListPagedSource interface
- Refactor postManager to use CachedManager and Sources pattern
- Refactor groupManager to use CachedManager and Sources pattern
- Clean up duplicate methods in groupService.ts
- Fix TypeScript errors and remove mock data

src/stores/postListSources.ts

@@ -0,0 +1,137 @@
+/**
+ * 帖子列表数据源抽象：游标、偏移分页实现同一契约，PostManager 只依赖接口。
+ */
+
+import { Post } from '../types';
+import { postService } from '../services/postService';
+import type { CursorPaginationRequest } from '../types/dto';
+
+export const POST_LIST_PAGE_SIZE = 20;
+
+/** 帖子列表类型 */
+export type PostListTab = 'hot' | 'latest' | 'follow';
+
+/** 单次拉取结果（一页或一批） */
+export interface PostListPage {
+  items: Post[];
+  /** 在当前源上是否还能再 loadNext 一页 */
+  hasMore: boolean;
+}
+
+/**
+ * 分页式帖子列表源：restart 后开始新序列；首次 loadNext 为第一页，之后为后续页。
+ */
+export interface IPostListPagedSource {
+  restart(): void;
+  loadNext(): Promise<PostListPage>;
+  /** 至少成功 loadNext 过一次且仍有下一页时为 true */
+  readonly hasMore: boolean;
+}
+
+/**
+ * 远端帖子列表（游标分页）
+ */
+export class NetworkCursorPostListPagedSource implements IPostListPagedSource {
+  private nextCursor: string | null = null;
+  private hasMoreAfterLastLoad = false;
+  private loadedOnce = false;
+  private readonly pageSize: number;
+  private readonly tab?: PostListTab;
+  private readonly channelId?: string;
+
+  constructor(
+    options: { tab?: PostListTab; channelId?: string; pageSize?: number } = {}
+  ) {
+    this.tab = options.tab;
+    this.channelId = options.channelId;
+    this.pageSize = options.pageSize ?? POST_LIST_PAGE_SIZE;
+  }
+
+  restart(): void {
+    this.nextCursor = null;
+    this.hasMoreAfterLastLoad = false;
+    this.loadedOnce = false;
+  }
+
+  get hasMore(): boolean {
+    return this.loadedOnce && this.hasMoreAfterLastLoad;
+  }
+
+  async loadNext(): Promise<PostListPage> {
+    const params: CursorPaginationRequest = {
+      cursor: this.nextCursor ?? '',
+      page_size: this.pageSize,
+      post_type: this.tab,
+    };
+
+    const result = await postService.getPostsCursor(params);
+
+    this.hasMoreAfterLastLoad = result.has_more ?? false;
+    this.nextCursor = result.next_cursor ?? null;
+    this.loadedOnce = true;
+
+    return { items: result.list ?? [], hasMore: this.hasMoreAfterLastLoad };
+  }
+}
+
+/**
+ * 远端帖子列表（偏移分页）
+ */
+export class NetworkOffsetPostListPagedSource implements IPostListPagedSource {
+  private nextPage = 1;
+  private hasMoreAfterLastLoad = false;
+  private loadedOnce = false;
+  private readonly pageSize: number;
+  private readonly tab?: PostListTab;
+  private readonly channelId?: string;
+
+  constructor(
+    options: { tab?: PostListTab; channelId?: string; pageSize?: number } = {}
+  ) {
+    this.tab = options.tab;
+    this.channelId = options.channelId;
+    this.pageSize = options.pageSize ?? POST_LIST_PAGE_SIZE;
+  }
+
+  restart(): void {
+    this.nextPage = 1;
+    this.hasMoreAfterLastLoad = false;
+    this.loadedOnce = false;
+  }
+
+  get hasMore(): boolean {
+    return this.loadedOnce && this.hasMoreAfterLastLoad;
+  }
+
+  async loadNext(): Promise<PostListPage> {
+    const result = await postService.getPosts(
+      this.nextPage,
+      this.pageSize,
+      this.tab,
+      this.channelId
+    );
+
+    const items = result.list ?? [];
+    const total = result.total ?? 0;
+    const totalPages = result.total_pages ?? 1;
+
+    this.hasMoreAfterLastLoad = this.nextPage < totalPages;
+    this.nextPage++;
+    this.loadedOnce = true;
+
+    return { items, hasMore: this.hasMoreAfterLastLoad };
+  }
+}
+
+/** 远端帖子列表分页策略 */
+export type RemotePostListSourceKind = 'cursor' | 'offset';
+
+export function createRemotePostListSource(
+  kind: RemotePostListSourceKind = 'cursor',
+  options: { tab?: PostListTab; channelId?: string; pageSize?: number } = {}
+): IPostListPagedSource {
+  if (kind === 'offset') {
+    return new NetworkOffsetPostListPagedSource(options);
+  }
+  return new NetworkCursorPostListPagedSource(options);
+}