### What problem does this PR solve?
As title.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Standardized the query parameter used when listing documents so
listings behave consistently across the web and client interfaces.
* Clarified the error message shown when a required dataset ID is
missing to give clearer guidance to users.
* **Tests**
* Updated test coverage to reflect the standardized dataset identifier
usage.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
- Add comprehensive test suite for chunk operations including:
- Test files for create, list, retrieve, update, and delete chunks
- Authorization tests
- Batch operations tests
- Update test configurations and common utilities
- Validate `important_kwd` and `question_kwd` fields are lists in
chunk_app.py
- Reorganize imports and clean up duplicate code
### Type of change
- [x] Add test cases
