docs(editor): improve editor-app build documentation and add build:rapier2d script

- Add `pnpm build:rapier2d` command to automate Rapier2D WASM build process
- Fix gen-src.mjs path to correctly locate thirdparty/rapier.js
- Update init.ts to work with new wasm-pack web target (auto-initialization)
- Fix behavior-tree-editor build config for asset-system dependency
- Update README_CN.md and README.md with simplified build instructions

packages/physics/rapier2d/scripts/gen-src.mjs

@@ -14,7 +14,7 @@ import { fileURLToPath } from 'url';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const packageRoot = join(__dirname, '..');
-const rapierRoot = join(packageRoot, '..', '..', 'thirdparty', 'rapier.js');
+const rapierRoot = join(packageRoot, '..', '..', '..', 'thirdparty', 'rapier.js');
 const srcTsDir = join(rapierRoot, 'src.ts');
 const src2dDir = join(rapierRoot, 'rapier-compat', 'src2d');
 const outputDir = join(packageRoot, 'src');

packages/physics/rapier2d/src/init.ts

@@ -1,12 +1,60 @@
-// @ts-ignore
-import wasmBase64 from "../pkg/rapier_wasm2d_bg.wasm";
+/**
+ * RAPIER initialization module with dynamic WASM loading support.
+ * RAPIER 初始化模块，支持动态 WASM 加载。
+ */
+
 import wasmInit from "../pkg/rapier_wasm2d";
-import base64 from "base64-js";
+
+/**
+ * Input types for WASM initialization.
+ * WASM 初始化的输入类型。
+ */
+export type InitInput =
+    | RequestInfo         // URL string or Request object
+    | URL                 // URL object
+    | Response            // Fetch Response object
+    | BufferSource        // ArrayBuffer or TypedArray
+    | WebAssembly.Module; // Pre-compiled module
+
+let initialized = false;
 
 /**
  * Initializes RAPIER.
  * Has to be called and awaited before using any library methods.
+ *
+ * 初始化 RAPIER。
+ * 必须在使用任何库方法之前调用并等待。
+ *
+ * @param input - WASM source (required). Can be URL, Response, ArrayBuffer, etc.
+ *                WASM 源（必需）。可以是 URL、Response、ArrayBuffer 等。
+ *
+ * @example
+ * // Load from URL | 从 URL 加载
+ * await RAPIER.init('wasm/rapier_wasm2d_bg.wasm');
+ *
+ * @example
+ * // Load from fetch response | 从 fetch 响应加载
+ * const response = await fetch('wasm/rapier_wasm2d_bg.wasm');
+ * await RAPIER.init(response);
+ *
+ * @example
+ * // Load from ArrayBuffer | 从 ArrayBuffer 加载
+ * const buffer = await fetch('wasm/rapier_wasm2d_bg.wasm').then(r => r.arrayBuffer());
+ * await RAPIER.init(buffer);
  */
-export async function init() {
-    await wasmInit(base64.toByteArray(wasmBase64 as unknown as string).buffer);
+export async function init(input?: InitInput): Promise<void> {
+    if (initialized) {
+        return;
+    }
+
+    await wasmInit(input);
+    initialized = true;
+}
+
+/**
+ * Check if RAPIER is already initialized.
+ * 检查 RAPIER 是否已初始化。
+ */
+export function isInitialized(): boolean {
+    return initialized;
 }