feat(editor): viewport overlay widget extension (#12035)

Closes: BS-3360

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

- **New Features**
  - Introduced a new viewport overlay widget, making it available as part of the workspace and enabling its integration into supported pages.

- **Refactor**
  - Updated internal imports and exports to utilize the new viewport overlay widget package.
  - Streamlined widget registration and extension mechanisms for improved modularity.

- **Chores**
  - Added configuration and project references to support the new viewport overlay widget package in the build system.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/all/src/extensions/view.ts

@@ -42,6 +42,7 @@ import { RemoteSelectionViewExtension } from '@blocksuite/affine-widget-remote-s
 import { ScrollAnchoringViewExtension } from '@blocksuite/affine-widget-scroll-anchoring/view';
 import { SlashMenuViewExtension } from '@blocksuite/affine-widget-slash-menu/view';
 import { ToolbarViewExtension } from '@blocksuite/affine-widget-toolbar/view';
+import { ViewportOverlayViewExtension } from '@blocksuite/affine-widget-viewport-overlay/view';
 
 import { MigratingViewExtension } from './migrating-view';
 
@@ -100,5 +101,6 @@ export function getInternalViewExtensions() {
     ScrollAnchoringViewExtension,
     SlashMenuViewExtension,
     ToolbarViewExtension,
+    ViewportOverlayViewExtension,
   ];
 }

blocksuite/affine/all/src/widgets/viewport-overlay/index.ts

@@ -0,0 +1 @@
+export * from '@blocksuite/affine-widget-viewport-overlay';

blocksuite/affine/all/src/widgets/viewport-overlay/view.ts

@@ -0,0 +1 @@
+export * from '@blocksuite/affine-widget-viewport-overlay/view';