refactor(editor): extract widgets (#12304)

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

- **New Features**
  - Introduced two new widgets: Edgeless Dragging Area and Note Slicer, now available for use.
  - Added extension support for these widgets, enabling enhanced interaction and integration within the application.

- **Chores**
  - Updated package configurations and workspace settings to include the new widgets and their dependencies.
  - Added project references and configuration files to support modular development and build processes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/widgets/note-slicer/src/view.ts

@@ -0,0 +1,23 @@
+import {
+  type ViewExtensionContext,
+  ViewExtensionProvider,
+} from '@blocksuite/affine-ext-loader';
+
+import { effects } from './effects';
+import { noteSlicerWidget } from './note-slicer';
+
+export class NoteSlicerViewExtension extends ViewExtensionProvider {
+  override name = 'affine-note-slicer-widget';
+
+  override effect() {
+    super.effect();
+    effects();
+  }
+
+  override setup(context: ViewExtensionContext) {
+    super.setup(context);
+    if (this.isEdgeless(context.scope)) {
+      context.register(noteSlicerWidget);
+    }
+  }
+}