✨ Add selection box extension

frontend/bindings/voidraft/internal/models/models.ts

@@ -421,6 +421,11 @@ export enum ExtensionID {
     ExtensionFold = "fold",
     ExtensionTextHighlight = "textHighlight",
 
+    /**
+     * 选择框
+     */
+    ExtensionCheckbox = "checkbox",
+
     /**
      * UI增强扩展
      * 小地图