feat(editor): add experimental feature citation (#11984)

Closes: [BS-3122](https://linear.app/affine-design/issue/BS-3122/footnote-definition-adapter-适配)
Closes: [BS-3123](https://linear.app/affine-design/issue/BS-3123/几个-block-card-view-适配-footnote-态)

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

- **New Features**
  - Introduced a new citation card component and web element for displaying citations.
  - Added support for citation-style rendering in attachment, bookmark, and linked document blocks.
  - Enabled citation parsing from footnote definitions in markdown for attachments, bookmarks, and linked docs.
  - Added a feature flag to enable or disable citation features.
  - Provided new toolbar logic to disable downloads for citation-style attachments.

- **Improvements**
  - Updated block models and properties to support citation identifiers.
  - Added localization and settings for the citation experimental feature.
  - Enhanced markdown adapters to recognize and process citation footnotes.
  - Included new constants and styles for citation card display.

- **Bug Fixes**
  - Ensured readonly state is respected in block interactions and rendering for citation blocks.

- **Documentation**
  - Added exports and effects for new citation components and features.

- **Tests**
  - Updated snapshots to include citation-related properties in block data.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/components/src/toggle-button/toggle-button.ts

@@ -1,3 +1,4 @@
+import { unsafeCSSVarV2 } from '@blocksuite/affine-shared/theme';
 import { WithDisposable } from '@blocksuite/global/lit';
 import { ToggleDownIcon, ToggleRightIcon } from '@blocksuite/icons/lit';
 import { ShadowlessElement } from '@blocksuite/std';
@@ -43,6 +44,12 @@ export class ToggleButton extends WithDisposable(ShadowlessElement) {
     .with-drag-handle .affine-block-children-container .toggle-icon {
       opacity: 0;
     }
+
+    .toggle-icon {
+      svg {
+        color: ${unsafeCSSVarV2('icon/primary', '#77757D')};
+      }
+    }
   `;
 
   override render() {
@@ -55,7 +62,6 @@ export class ToggleButton extends WithDisposable(ShadowlessElement) {
         ${ToggleDownIcon({
           width: '16px',
           height: '16px',
-          style: 'color: #77757D',
         })}
       </div>
     `;
@@ -70,7 +76,6 @@ export class ToggleButton extends WithDisposable(ShadowlessElement) {
         ${ToggleRightIcon({
           width: '16px',
           height: '16px',
-          style: 'color: #77757D',
         })}
       </div>
     `;