build: add remote-only mode lang package stub and replacement logic

add empty-lang-stub.js to stub lang package files in remote-only mode,
add webpack plugin logic to replace lang files with stub to reduce bundle size

common/js/empty-lang-stub.js

@@ -0,0 +1,15 @@
+// ============================================================
+// 空 lang 包占位
+//
+// 在 source === 'remote-only' 模式下, lang/ 目录下的所有 .js 会被
+// webpack.NormalModuleReplacementPlugin 替换为这个 stub.
+//
+// 设计要点:
+//   - 导出 default 对象, 结构与真实 lang 包一致: { lang: {...} }
+//   - lang 字段是空对象, 让 lang() 函数 fallback 路径不报错
+//   - 不导出 named export, 避免 tree-shaking 把整个 stub 干掉
+// ============================================================
+
+export default {
+	lang: {}
+};

vue.config.js

@@ -90,6 +90,66 @@ function _readManifestBase(manifestPath) {
   return '';
 }
 
+/**
+ * 读取 langConfig.source, 用于构建期判断是否启用 lang/ 排除策略
+ * 用 fs 静态解析, 避免 webpack 把整个 config-external.js 链入 vue.config 编译路径
+ */
+function _readLangSource() {
+	try {
+		const content = fs.readFileSync(path.join(__dirname, 'common/js/config-external.js'), 'utf-8');
+		const match = content.match(/source:\s*['"]([\w-]+)['"]/);
+		return match ? match[1] : null;
+	} catch (e) {
+		return null;
+	}
+}
+
+/**
+ * 通用Webpack的资源替换插件
+ */
+class NormalModuleReplacementPlugin {
+	constructor(resourceRegExp, newResource) {
+		this.resourceRegExp = resourceRegExp;
+		this.newResource = newResource;
+	}
+
+	apply(compiler) {
+		const resourceRegExp = this.resourceRegExp;
+		const newResource = this.newResource;
+		
+		compiler.hooks.normalModuleFactory.tap(
+			"NormalModuleReplacementPlugin",
+			nmf => {
+				nmf.hooks.beforeResolve.tap("NormalModuleReplacementPlugin", result => {
+					if (!result) return;
+					if (resourceRegExp.test(result.request)) {
+						if (typeof newResource === "function") {
+							newResource(result);
+						} else {
+							result.request = newResource;
+						}
+					}
+					return result;
+				});
+				nmf.hooks.afterResolve.tap("NormalModuleReplacementPlugin", result => {
+					if (!result) return;
+					if (resourceRegExp.test(result.resource)) {
+						if (typeof newResource === "function") {
+							newResource(result);
+						} else {
+							result.resource = path.resolve(
+								path.dirname(result.resource),
+								newResource
+							);
+						}
+					}
+					return result;
+				});
+			}
+		);
+	}
+}
+
 /**
  * 自定义 webpack 插件：在通用产物（vendor.js）中内联注入版本数据
  * 利用 emit 钩子在资源写入磁盘前处理，支持 HMR（每次重编译都会自动注入）
@@ -352,9 +412,36 @@ class VersionInjectPlugin {
 
 // 导出配置
 module.exports = {
-  productionSourceMap: false,
-  configureWebpack: config => {
-    console.log('config.mode = ', config.mode);
+	productionSourceMap: false,
+	configureWebpack: config => {
+		console.log('config.mode = ', config.mode);
+
+		// lang/ 目录排除: 仅在 remote-only 模式下生效
+		// 原理: webpack 把 require(`@/lang/${lang}/${path}.js`) 解析为 ContextModule,
+		//       会扫描并打包 lang/ 下所有 .js. 替换为 stub 后, 真正的 lang 文件不进 bundle.
+		// 条件: source === 'remote-only' (由 common/js/config-external.js 配置)
+		const langSource = _readLangSource();
+		if (langSource === 'remote-only') {
+			try {
+				const webpack = require('webpack');
+				const stubPath = path.resolve(__dirname, 'common/js/empty-lang-stub.js');
+        console.log(`[vue.config] config.plugins.length = ${config.plugins.length}`);
+        if (webpack?.NormalModuleReplacementPlugin){
+          config.plugins.push(
+          	new NormalModuleReplacementPlugin(
+          		// 匹配解析后的绝对路径: .../lang/xxx/yyy.js
+          		/[\\/]lang[\\/].+\.js$/,
+          		stubPath
+          	)
+          );
+          console.log(`[vue.config] ✅ lang/ 目录已替换为 stub (source=remote-only) — 节省 lang 包体积`);
+        }
+			} catch (e) {
+				console.error('[vue.config] 配置 lang/ 排除失败:', e.message);
+			}
+		} else {
+			console.log(`[vue.config] lang/ 目录保留 (source=${langSource || 'unknown'})`);
+		}
 
     if (config.mode === 'production') {
       console.log('开始尝试配置极限压缩');