Refactor: Migrate from MyBatis-Plus to MyBatis-Plus-Join

[hsiong]

Description:
We need to refactor the project to replace the existing MyBatis-Plus implementation with MyBatis-Plus-Join.
This change aims to simplify complex multi-table queries and improve code readability and maintainability.

Tasks:

• Replace BaseMapper and related query wrappers with their MyBatis-Plus-Join equivalents.
• Refactor existing service and repository layers to use MPJQueryWrapper / MPJLambdaWrapper.
• Update join query logic in DAO/Mapper classes.
• Ensure all unit tests pass and adjust tests as necessary.
• Verify that pagination and sorting work correctly with join queries.

Expected Result:
All database operations should function the same as before, but now use MyBatis-Plus-Join for multi-table queries.