feat(editor): slash menu and toolbar widget extensions (#12002)

Closes: BS-3226
Closes: BS-3227
Closes: BS-3228
Closes: BS-3229

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

- **New Features**
  - Introduced new view extensions for remote selection, scroll anchoring, slash menu, and toolbar widgets, enhancing customization and integration capabilities.

- **Refactor**
  - Updated export paths and module structure for widget-related packages to improve modularity and accessibility.
  - Reorganized internal dependencies and removed redundant widget imports from core block packages.
  - Refactored edgeless-related widgets and components to use a standardized scope interface for improved context and state management.
  - Centralized graphics controller access and slot management through standardized context objects.

- **Chores**
  - Added and updated dependencies to streamline extension loading and workspace management.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/widgets/toolbar/tsconfig.json

@@ -11,6 +11,7 @@
     { "path": "../../blocks/surface" },
     { "path": "../../blocks/table" },
     { "path": "../../components" },
+    { "path": "../../ext-loader" },
     { "path": "../../model" },
     { "path": "../../shared" },
     { "path": "../../../framework/global" },