feat(core): code artifact tool (#13015)

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src="https://github.com/user-attachments/assets/429ec60a-48a9-490b-b45f-3ce7150ef32a"
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#### PR Dependency Tree


* **PR #13015** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Introduced a new AI tool for generating self-contained HTML artifacts,
including a dedicated interface for previewing, copying, and downloading
generated HTML.
* Added syntax highlighting and preview capabilities for HTML artifacts
in chat and tool panels.
* Integrated the new HTML artifact tool into the AI chat prompt and
Copilot toolset.

* **Enhancements**
* Improved artifact preview panel layout and sizing for a better user
experience.
* Enhanced HTML preview components to support both model-based and raw
HTML rendering.

* **Dependency Updates**
  * Added the "shiki" library for advanced syntax highlighting.

* **Bug Fixes**
  * None.

* **Chores**
* Updated internal imports and code structure to support new features
and maintain consistency.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/code/src/index.ts

@@ -2,7 +2,9 @@ export * from './adapters';
 export * from './clipboard';
 export * from './code-block';
 export * from './code-block-config';
+export * from './code-block-service';
 export * from './code-preview-extension';
 export * from './code-toolbar';
+export * from './highlight/const';
 export * from './turbo/code-layout-handler';
 export * from './turbo/code-painter.worker';