Closes: [BS-3122](https://linear.app/affine-design/issue/BS-3122/footnote-definition-adapter-适配)
Closes: [BS-3123](https://linear.app/affine-design/issue/BS-3123/几个-block-card-view-适配-footnote-态)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Introduced a new citation card component and web element for displaying citations.
- Added support for citation-style rendering in attachment, bookmark, and linked document blocks.
- Enabled citation parsing from footnote definitions in markdown for attachments, bookmarks, and linked docs.
- Added a feature flag to enable or disable citation features.
- Provided new toolbar logic to disable downloads for citation-style attachments.
- **Improvements**
- Updated block models and properties to support citation identifiers.
- Added localization and settings for the citation experimental feature.
- Enhanced markdown adapters to recognize and process citation footnotes.
- Included new constants and styles for citation card display.
- **Bug Fixes**
- Ensured readonly state is respected in block interactions and rendering for citation blocks.
- **Documentation**
- Added exports and effects for new citation components and features.
- **Tests**
- Updated snapshots to include citation-related properties in block data.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
