feat(business): enhance block editor with segment conversion and data persistence

- Implement `segmentsToBlocks` utility to convert message segments into editable blocks.
- Update `BlockEditor` and `useBlockEditor` to support initial block loading and improved image upload handling.
- Add logic to `CreatePostScreen` to automatically switch to long-post mode when image segments are detected and preserve data when toggling modes.
- Update `AboutScreen` to make the ICP filing number clickable.
- Refactor mapper imports to use the updated data model paths.

src/services/mappers/UserMapper.ts

@@ -3,7 +3,7 @@
  * 负责 User 模型与 API 响应、数据库记录之间的转换
  */
 
-import { UserModel } from '../models';
+import { UserModel } from '../../data/models';
 import type { UserDTO } from '../../types/dto';
 
 // 数据库用户记录类型