Close [BS-3391](https://linear.app/affine-design/issue/BS-3391/无法从note中拖出embed-synced-doc到白板)
### Before
can not hover on drag handle
https://github.com/user-attachments/assets/5596538e-e922-4d7f-8188-b719b234f3ee
### After
can hover on drag handle
https://github.com/user-attachments/assets/855743ec-7601-48a8-8453-cd5aa395bd06
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **Bug Fixes**
- Improved detection of hovering over notes in edgeless mode, ensuring the drag handle appears correctly when hovering on the background of a selected note.
- Enhanced background style updates for edgeless notes, providing more accurate visual feedback.
- **Tests**
- Added a test to verify that the drag handle is visible when hovering over the background of a selected edgeless note.
- Updated undo/redo tests to improve accuracy of background color evaluation.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **Refactor**
- Unified internal data access by replacing all references from `doc` to `store` across all components, blocks, widgets, and utilities. This affects how readonly state, block operations, and service retrieval are handled throughout the application.
- **Tests**
- Updated all test utilities and test cases to use `store` instead of `doc` for document-related operations.
- **Chores**
- Updated context providers and property names to reflect the change from `doc` to `store` for improved consistency and maintainability.
No user-facing features or behaviors have changed.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->