chore: 移除第三方引擎引用，改进 README 专业度

packages/engine-core/src/SortingLayer.ts

@@ -2,8 +2,8 @@
  * 排序层系统 - 控制渲染顺序
  * Sorting Layer System - Controls render order
  *
- * 类似 Unity 的 Sorting Layer + Order in Layer 系统。
- * Similar to Unity's Sorting Layer + Order in Layer system.
+ * 提供排序层和层内排序功能，用于精确控制 2D 对象的渲染顺序。
+ * Provides sorting layer and order-in-layer functionality for precise 2D rendering order control.
  *
  * @example
  * ```typescript

packages/particle/src/ClickFxComponent.ts

@@ -2,9 +2,6 @@
  * 点击特效组件 - 在点击位置播放粒子效果
  * Click FX Component - Play particle effects at click position
  *
- * 类似 Unity 的 ShowFxWhenClicked 功能。
- * Similar to Unity's ShowFxWhenClicked functionality.
- *
  * @example
  * ```typescript
  * // 在编辑器中添加此组件到相机或空实体上

packages/sdk/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@esengine/sdk",
     "version": "1.0.0",
-    "description": "Unified SDK entry point for ESEngine - like Unity's 'using UnityEngine'",
+    "description": "Unified SDK entry point for ESEngine - single import for all engine modules",
     "main": "dist/index.js",
     "module": "dist/index.js",
     "types": "dist/index.d.ts",