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 -->

---------

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

blocksuite/affine/shared/src/services/icon-picker-service.ts

@@ -0,0 +1 @@
+export * from './icon-picker-service/index.js';

blocksuite/affine/shared/src/services/icon-picker-service/index.ts

@@ -0,0 +1,29 @@
+import type { UniComponent } from '@blocksuite/affine-shared/types';
+import { createIdentifier } from '@blocksuite/global/di';
+export enum IconType {
+  Emoji = 'emoji',
+  AffineIcon = 'affine-icon',
+  Blob = 'blob',
+}
+
+export type IconData =
+  | {
+      type: IconType.Emoji;
+      unicode: string;
+    }
+  | {
+      type: IconType.AffineIcon;
+      name: string;
+      color: string;
+    }
+  | {
+      type: IconType.Blob;
+      blob: Blob;
+    };
+
+export interface IconPickerService {
+  iconPickerComponent: UniComponent<{ onSelect?: (data?: IconData) => void }>;
+}
+
+export const IconPickerServiceIdentifier =
+  createIdentifier<IconPickerService>('IconPickerService');

blocksuite/affine/shared/src/services/index.ts

@@ -13,6 +13,7 @@ export * from './feature-flag-service';
 export * from './file-size-limit-service';
 export * from './font-loader';
 export * from './generate-url-service';
+export * from './icon-picker-service';
 export * from './link-preview-service';
 export * from './native-clipboard-service';
 export * from './notification-service';