Refactor: Remove original Dart references from comments across multiple files

- Updated comments in various components, schemas, and repositories to remove references to original Dart files.
- Ensured consistency in documentation while maintaining the context of the code.

src/utils/date.ts

@@ -1,7 +1,7 @@
 /**
  * 日期工具
  *
- * 原始 Dart: lib/utils/date_utils.dart（app_date_utils.DateUtils）
+ * 
  *
  * 业务侧用 `formatDate(date)` 生成聊天时间戳，`todayString()` 用于每日配额 key。
  */