refactor(stores): reorganize flat store files into modular directory structure

Migrate from flat file organization to modular directory structure under src/stores/:

- auth/: authStore, registerStore, verificationStore, sessionStore
- call/: callStore
- settings/: chatSettingsStore, themeStore
- ui/: homeTabBarVisibilityStore, homeTabPressStore
- utils/: routePayloadCache
- group/sources.ts, group/profileResolver.ts
- message/sources.ts
- post/sources.ts

Update all import paths across components and screens to use new module paths. Maintain backward compatibility through deprecated re-export files for gradual migration.

src/stores/group/index.ts

@@ -23,5 +23,32 @@ export {
   type UseGroupMembersResult,
 } from './hooks';
 
+// ==================== 数据源 ====================
+export {
+  GROUP_LIST_PAGE_SIZE,
+  GROUP_MEMBER_LIST_PAGE_SIZE,
+  type GroupListPage,
+  type IGroupListPagedSource,
+  type GroupMemberListPage,
+  type IGroupMemberListPagedSource,
+  type GroupMemberListSourceKind,
+  type ICursorGroupMemberListPagedSource,
+  type RemoteGroupListSourceKind,
+  NetworkCursorGroupListPagedSource,
+  NetworkOffsetGroupListPagedSource,
+  SqliteGroupListPagedSource,
+  NetworkCursorGroupMemberListPagedSource,
+  NetworkOffsetGroupMemberListPagedSource,
+  SqliteGroupMemberListPagedSource,
+  CursorGroupMemberListSource,
+  OffsetGroupMemberListSource,
+  createRemoteGroupListSource,
+  createRemoteGroupMemberListSource,
+  createCursorGroupMemberListSource,
+} from './sources';
+
+// ==================== 工具 ====================
+export { enrichGroupMembersWithUserProfiles } from './profileResolver';
+
 // ==================== 默认导出 ====================
 export { default } from './GroupManager';