feat: 添加跨平台运行时、资产系统和UI适配功能 (#256)

* feat(platform-common): 添加WASM加载器和环境检测API

* feat(rapier2d): 新增Rapier2D WASM绑定包

* feat(physics-rapier2d): 添加跨平台WASM加载器

* feat(asset-system): 添加运行时资产目录和bundle格式

* feat(asset-system-editor): 新增编辑器资产管理包

* feat(editor-core): 添加构建系统和模块管理

* feat(editor-app): 重构浏览器预览使用import maps

* feat(platform-web): 添加BrowserRuntime和资产读取

* feat(engine): 添加材质系统和着色器管理

* feat(material): 新增材质系统和着色器编辑器

* feat(tilemap): 增强tilemap编辑器和动画系统

* feat(modules): 添加module.json配置

* feat(core): 添加module.json和类型定义更新

* chore: 更新依赖和构建配置

* refactor(plugins): 更新插件模板使用ModuleManifest

* chore: 添加第三方依赖库

* chore: 移除BehaviourTree-ai和ecs-astar子模块

* docs: 更新README和文档主题样式

* fix: 修复Rust文档测试和添加rapier2d WASM绑定

* fix(tilemap-editor): 修复画布高DPI屏幕分辨率适配问题

* feat(ui): 添加UI屏幕适配系统(CanvasScaler/SafeArea)

* fix(ecs-engine-bindgen): 添加缺失的ecs-framework-math依赖

* fix: 添加缺失的包依赖修复CI构建

* fix: 修复CodeQL检测到的代码问题

* fix: 修复构建错误和缺失依赖

* fix: 修复类型检查错误

* fix(material-system): 修复tsconfig配置支持TypeScript项目引用

* fix(editor-core): 修复Rollup构建配置添加tauri external

* fix: 修复CodeQL检测到的代码问题

* fix: 修复CodeQL检测到的代码问题

packages/platform-web/src/index.ts

@@ -1,29 +1,69 @@
 /**
  * @esengine/platform-web
  *
- * Web/H5 平台适配器 - 仅包含平台差异代码
- * 通用运行时逻辑在 @esengine/runtime-core
+ * Web/H5 Platform Adapter
+ * Web/H5 平台适配器
+ *
+ * Provides browser-specific implementations:
+ * - BrowserRuntime: Main entry point for game builds
+ * - BrowserAssetReader: Asset loading via fetch API
+ * - Web subsystems: Canvas, Input, Storage, WASM
  *
  * @packageDocumentation
  */
 
-// Web 平台子系统
+// ============================================
+// Runtime (main entry for game builds)
+// ============================================
+export {
+    BrowserRuntime,
+    create,
+    type RuntimeConfig
+} from './BrowserRuntime';
+
+// Default export for convenient usage in game builds
+export { default } from './BrowserRuntime';
+
+// Asset reader
+export { BrowserAssetReader } from './BrowserAssetReader';
+
+// ============================================
+// Web Platform Subsystems
+// ============================================
 export { WebCanvasSubsystem } from './subsystems/WebCanvasSubsystem';
 export { WebInputSubsystem } from './subsystems/WebInputSubsystem';
 export { WebStorageSubsystem } from './subsystems/WebStorageSubsystem';
 export { WebWASMSubsystem } from './subsystems/WebWASMSubsystem';
 
-// Web 特定系统
+// ============================================
+// Web-specific Systems
+// ============================================
 export { Canvas2DRenderSystem } from './systems/Canvas2DRenderSystem';
 
+// ============================================
+// Platform Detection Utilities
+// ============================================
+
+/**
+ * Check if running in web browser
+ * 检查是否在浏览器中运行
+ */
 export function isWebPlatform(): boolean {
     return typeof window !== 'undefined' && typeof document !== 'undefined';
 }
 
+/**
+ * Get canvas element by ID
+ * 根据 ID 获取 canvas 元素
+ */
 export function getWebCanvas(canvasId: string): HTMLCanvasElement | null {
     return document.getElementById(canvasId) as HTMLCanvasElement | null;
 }
 
+/**
+ * Create a new canvas element
+ * 创建新的 canvas 元素
+ */
 export function createWebCanvas(width: number, height: number): HTMLCanvasElement {
     const canvas = document.createElement('canvas');
     canvas.width = width;