feat: 更新填充组图层背景命令，增强图层管理和颜色填充功能，优化图层选择和渲染逻辑

src/component/Canvas/CanvasEditor/utils/helper.js

@@ -602,7 +602,7 @@ export function getObjectZIndex(canvas, targetObj) {
  * @param {boolean} renderAll 是否立即渲染，默认true
  * @returns {boolean} 是否成功插入
  */
-export function insertObjectAtZIndex(canvas, object, zIndex, renderAll = true) {
+export function insertObjectAtZIndex(canvas, object, zIndex, renderAll = true, isReplace = false) {
   if (!canvas || !object || zIndex < 0) {
     return false;
   }
@@ -612,7 +612,7 @@ export function insertObjectAtZIndex(canvas, object, zIndex, renderAll = true) {
     const maxIndex = canvas.getObjects().length;
     const safeZIndex = Math.min(zIndex, maxIndex);
 
-    canvas.insertAt(object, safeZIndex, false);
+    canvas.insertAt(object, safeZIndex, isReplace);
 
     if (renderAll) {
       canvas.renderAll();