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## Summary by CodeRabbit
* **New Features**
* In-tree icon picker for Callout blocks (emoji, app icons, images) with
popup UI and editor-wide extension/service.
* Callout toolbar adds background color presets, an icon-picker action,
and a destructive Delete action.
* **Refactor**
* Replaced legacy emoji workflow with icon-based rendering, updated
state, styling, and lifecycle for callouts.
* **Tests**
* Updated callout E2E to reflect new default icon and picker behavior.
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Co-authored-by: L-Sun <zover.v@gmail.com>
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
- New Features
- Press Enter inside a callout splits the paragraph at the cursor into a
new focused paragraph.
- Clicking an empty callout inserts and focuses a new paragraph; emoji
menu behavior unchanged.
- New command to convert a callout paragraph to callout/selection flow
for Backspace handling.
- New native API: ShareableContent.isUsingMicrophone(processId).
- Bug Fixes
- Backspace inside callout paragraphs now merges or deletes text
predictably and selects the callout when appropriate.
- Style
- Callout layout refined: top-aligned content and adjusted emoji
spacing.
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