feat(editor): support preview mode in code block (#11805)

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

- **New Features**
  - Introduced a preview mode for code blocks, allowing users to toggle between code and rendered previews (e.g., HTML output) directly within the editor.
  - Added a preview toggle button to the code block toolbar for supported languages.
  - Enabled dynamic rendering of code block previews using a shared WebContainer, allowing live HTML previews in an embedded iframe.
  - Added HTML preview support with loading and error states for enhanced user feedback.
  - Integrated the preview feature as a view extension provider for seamless framework support.

- **Bug Fixes**
  - Improved toolbar layout and button alignment for a cleaner user interface.

- **Tests**
  - Added end-to-end tests to verify the new code block preview functionality and language switching behavior.

- **Chores**
  - Updated development server configuration to include enhanced security headers.
  - Added a new runtime dependency for WebContainer support.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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

@@ -3,6 +3,7 @@ export * from './clipboard';
 export * from './code-block';
 export * from './code-block-config';
 export * from './code-block-spec';
+export * from './code-preview-extension';
 export * from './code-toolbar';
 export * from './turbo/code-layout-handler';
 export * from './turbo/code-painter.worker';