fengmk2 73402c8447 feat(server): parse ydoc to markdown (#12812) ...

close AI-190

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced an endpoint to retrieve a document's markdown content and
title.
- Added backend support for parsing document snapshots directly into
markdown format.

- **Tests**
- Added comprehensive tests and snapshot files for markdown retrieval,
including success and error scenarios.
- Improved test coverage for content type validation and markdown
parsing utilities.

- **Documentation**
- Enhanced internal documentation through detailed test cases and
snapshot references for new markdown features.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->








#### PR Dependency Tree


* **PR #12812** 👈
  * **PR #12846**
    * **PR #12811**

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

2025-06-19 09:14:00 +08:00

..

backend

feat(server): parse ydoc to markdown (#12812)

2025-06-19 09:14:00 +08:00

common

feat(core): add stream object api (#12841)

2025-06-19 09:13:18 +08:00

frontend

feat(core): add stream object api (#12841)

2025-06-19 09:13:18 +08:00