feat(editor): add page dragging area widget extension (#12045)

Closes: BS-3364

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

- **New Features**
  - Introduced a new "Page Dragging Area" widget, enabling enhanced block selection and drag area detection within the user interface.
  - Added utilities for more precise block selection based on rectangular selection areas.

- **Improvements**
  - Integrated the new widget into the view extension system for consistent behavior across supported views.
  - Enhanced clipboard handling with comprehensive adapter configurations for various data types.

- **Refactor**
  - Streamlined widget registration and block selection logic for improved maintainability and modularity.
  - Removed legacy widget exports and registrations to centralize widget management.

- **Chores**
  - Updated workspace and TypeScript configurations to support the new widget module.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/root/src/effects.ts

@@ -21,15 +21,10 @@ import {
   PageRootBlockComponent,
   PreviewRootBlockComponent,
 } from './index.js';
-import {
-  AFFINE_PAGE_DRAGGING_AREA_WIDGET,
-  AffinePageDraggingAreaWidget,
-} from './widgets/page-dragging-area/page-dragging-area.js';
 
 export function effects() {
   // Register components by category
   registerRootComponents();
-  registerWidgets();
   registerEdgelessToolbarComponents();
   registerMiscComponents();
 }
@@ -44,13 +39,6 @@ function registerRootComponents() {
   );
 }
 
-function registerWidgets() {
-  customElements.define(
-    AFFINE_PAGE_DRAGGING_AREA_WIDGET,
-    AffinePageDraggingAreaWidget
-  );
-}
-
 function registerEdgelessToolbarComponents() {
   // Tool buttons
   customElements.define('edgeless-link-tool-button', EdgelessLinkToolButton);