Closes: [BS-3508](https://linear.app/affine-design/issue/BS-3508/google-docs复制内容到affine时自动加粗问题)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Improved detection of bold, italic, underline, and strike-through formatting in imported HTML, supporting both tags and inline CSS styles.
- Enhanced handling of inline elements containing block-level children to ensure correct formatting and structure during HTML import.
- Introduced a plugin that converts inline elements with block-level children into block elements, preserving original tag information.
- **Bug Fixes**
- Resolved issues where block-level elements nested inside inline tags could cause incorrect formatting or structure.
- **Tests**
- Added comprehensive test coverage for HTML formatting conversions and plugin behavior to ensure accuracy and reliability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->