fix(icon-service): Use plain Map instance for message transfer

src/components/icon/icon-state.broadcast.ts

@@ -84,8 +84,12 @@ export class IconsStateBroadcast {
 
     this.send({
       actionType: ActionType.SyncState,
-      collections: this._getUserSetCollection(this._iconsCollection),
-      references: this._getUserRefsCollection(this._iconReferences),
+      collections: this._getUserSetCollection(
+        this._iconsCollection.toPlainMap()
+      ),
+      references: this._getUserRefsCollection(
+        this._iconReferences.toPlainMap()
+      ),
       origin: IconsStateBroadcast._origin,
     });
   }
@@ -104,7 +108,7 @@ export class IconsStateBroadcast {
   }
 
   private _getUserRefsCollection(
-    collections: IconsCollection<IconMeta>
+    collections: Map<string, Map<string, IconMeta>>
   ): IconsCollection<IconMeta> {
     const userSetIcons = createIconDefaultMap<string, IconMeta>();
 
@@ -120,7 +124,7 @@ export class IconsStateBroadcast {
   }
 
   private _getUserSetCollection(
-    collections: IconsCollection<SvgIcon>
+    collections: Map<string, Map<string, SvgIcon>>
   ): IconsCollection<SvgIcon> {
     const userSetIcons = createIconDefaultMap<string, SvgIcon>();
 

src/components/icon/registry/default-map.ts

@@ -55,6 +55,27 @@ class DefaultMap<K, V> extends Map<K, V> {
 
     return this.get(key) as V;
   }
+
+  /**
+   * Converts the DefaultMap to a plain Map for structured cloning.
+   *
+   * @remarks
+   * This method helps with cross-browser compatibility when using BroadcastChannel
+   * or postMessage, as custom Map subclasses are not properly cloned in Safari.
+   * Returns a plain Map that is guarantied to be structured cloneable across all browsers.
+   *
+   * @returns A plain Map with the same entries as this DefaultMap.
+   *
+   * @example
+   * ```typescript
+   * const defaultMap = new DefaultMap<string, Set<number>>();
+   * const plainMap = defaultMap.toPlainMap();
+   * channel.postMessage({ data: plainMap });
+   * ```
+   */
+  public toPlainMap(): Map<K, V> {
+    return new Map(this.entries());
+  }
 }
 
 /**