refactor(editor): new icon picker (#13658)

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

* **New Features**
* In-tree icon picker for Callout blocks (emoji, app icons, images) with
popup UI and editor-wide extension/service.
* Callout toolbar adds background color presets, an icon-picker action,
and a destructive Delete action.

* **Refactor**
* Replaced legacy emoji workflow with icon-based rendering, updated
state, styling, and lifecycle for callouts.

* **Tests**
  * Updated callout E2E to reflect new default icon and picker behavior.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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Co-authored-by: L-Sun <zover.v@gmail.com>

packages/frontend/core/src/modules/index.ts

@@ -33,6 +33,7 @@ import { configureFavoriteModule } from './favorite';
 import { configureFeatureFlagModule } from './feature-flag';
 import { configureGlobalContextModule } from './global-context';
 import { configureI18nModule } from './i18n';
+import { configureIconPickerModule } from './icon-picker';
 import { configureImportClipperModule } from './import-clipper';
 import { configureImportTemplateModule } from './import-template';
 import { configureIntegrationModule } from './integration';
@@ -132,4 +133,5 @@ export function configureCommonModules(framework: Framework) {
   configureCommentModule(framework);
   configureDocSummaryModule(framework);
   configurePaywallModule(framework);
+  configureIconPickerModule(framework);
 }