### Problem
●In edgeless mode, when starting to edit, `note-block` exhibits two
types of invalid caret behavior:
(1)**Title Region Misalignment**: Clicking on the title region
incorrectly generates the caret in the first line of the note content,
rather than in the title itself.
(2)**Vanishing Caret at Line End**: When clicking in the empty space
beyond the end of a text section, the caret appears momentarily at the
line's end but disappears immediately.
●The following video demonstrates these issues:
https://github.com/user-attachments/assets/db9c2c50-709f-4d32-912c-0f01841d2024
### Solution
●**Title Click Interception**: Added a check to determine if the click
coordinates fall in the title region. If so, the caret positioning is
now handled by a dedicated logic path. Otherwise, it falls back to the
existing note-content logic as before.
●**Range Normalization**: When the generated `range.startContainer` is
not a `TextNode`, try to find a most appropriate `TextNode` and update
the `range` accordingly.
### After
●The video below shows the behavior after this fix.
https://github.com/user-attachments/assets/b2f70b64-1fc6-4049-8379-8bcf3a488a05
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Clicking a page block title no longer creates unwanted paragraphs and
reliably focuses the title.
* Paragraph creation now occurs only when needed and focus is applied
only after successful creation.
* Click coordinates are clamped to container bounds to prevent misplaced
cursors or focus.
* **Improvements**
* Caret normalization: clicks place the caret at the last meaningful
text position for consistent single-cursor behavior.
* **Tests**
* Added end-to-end coverage for caret placement and focus transitions.
* New ratio-based click/double-click test utilities and a helper for
double-clicking note bodies.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Introduced a new slider component for line width selection, providing a more interactive and streamlined UI.
- Added support for using the slider component across relevant panels.
- **Improvements**
- Simplified the line width selection panel for easier use and improved maintainability.
- Enhanced event handling to prevent dropdowns from closing when interacting with the panel.
- **Bug Fixes**
- Improved event propagation control within the line styles panel.
- **Chores**
- Updated package exports to include the new slider component.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Close [BS-3288](https://linear.app/affine-design/issue/BS-3288/从note转换-linked-doc-时，默认把note的第一行填入doc拟定的标题)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- When converting a note block to a linked document, the initial document title now uses the first paragraph in the note (if available) as a placeholder.
- **Tests**
- Updated tests to verify that the linked document creation modal pre-fills the title with the note's first paragraph and checks for correct paragraph order.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
### What Changes
- Refactors the `notify` function call with undo button. It is called `notifyWithUndo`, which can associate the visibility of the `NotificationCard` with the top undo item in history stack, such as undo by shortcut `Cmd+Z`.
- change icon of the "Insert into page" button. Close [BS-3267](https://linear.app/affine-design/issue/BS-3267/frame和group的insert-into-page图标也更换一下)
### TL;DR
Moved editor components from BlockSuite presets to AFFiNE core and updated imports accordingly.
### What changed?
- Relocated `EdgelessEditor` and `PageEditor` components from BlockSuite presets to AFFiNE core
- Removed basic editor examples from playground
- Updated import paths across the codebase to reference new component locations
- Added editor effects registration in AFFiNE core
- Removed editor exports from BlockSuite presets
### How to test?
1. Launch the application
2. Verify both page and edgeless editors load correctly
3. Confirm editor functionality remains intact including:
- Document editing
- Mode switching
- Editor toolbars and controls
- Multiple editor instances
### Why make this change?
This change better aligns with AFFiNE's architecture by moving editor components closer to where they are used. It reduces coupling with BlockSuite presets and gives AFFiNE more direct control over editor customization and implementation.
Close [BS-2315](https://linear.app/affine-design/issue/BS-2315/page-block-header)
### What Changes
- Add header toolbar to page block (the first note in canvas)
- Add e2e tests
- Add some edgeless e2e test utils. **The package `@blocksuite/affine` was added to `"@affine-test/kit"`**
congzhou09
