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/package.json

@@ -0,0 +1,42 @@
+{
+  "name": "@blocksuite/affine-widget-note-slicer",
+  "description": "Affine note slicer widget.",
+  "type": "module",
+  "scripts": {
+    "build": "tsc"
+  },
+  "sideEffects": false,
+  "keywords": [],
+  "author": "toeverything",
+  "license": "MIT",
+  "dependencies": {
+    "@blocksuite/affine-block-note": "workspace:*",
+    "@blocksuite/affine-block-surface": "workspace:*",
+    "@blocksuite/affine-components": "workspace:*",
+    "@blocksuite/affine-ext-loader": "workspace:*",
+    "@blocksuite/affine-model": "workspace:*",
+    "@blocksuite/affine-shared": "workspace:*",
+    "@blocksuite/affine-widget-edgeless-selected-rect": "workspace:*",
+    "@blocksuite/global": "workspace:*",
+    "@blocksuite/icons": "^2.2.12",
+    "@blocksuite/std": "workspace:*",
+    "@lit/context": "^1.1.2",
+    "@preact/signals-core": "^1.8.0",
+    "@toeverything/theme": "^1.1.14",
+    "lit": "^3.2.0",
+    "rxjs": "^7.8.1",
+    "yjs": "^13.6.21"
+  },
+  "exports": {
+    ".": "./src/index.ts",
+    "./effects": "./src/effects.ts",
+    "./view": "./src/view.ts"
+  },
+  "files": [
+    "src",
+    "dist",
+    "!src/__tests__",
+    "!dist/__tests__"
+  ],
+  "version": "0.21.0"
+}