diff --git a/frontend/package.json b/frontend/package.json
index 6b5c08b..1d159a8 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -7,8 +7,9 @@
     "test": "node --test test/*.test.mjs",
     "prebuild": "node ./scripts/write-build-version.mjs",
     "dev": "node ./scripts/write-build-version.mjs && vite --configLoader native",
-    "build": "vite build && node ./scripts/verify-planning-entry.mjs",
+    "build": "node ./scripts/verify-router-lazy.mjs && vite build && node ./scripts/verify-planning-entry.mjs",
     "check": "npm run lint && npm test && npm run build",
+    "verify:router-lazy": "node ./scripts/verify-router-lazy.mjs",
     "verify:public-build": "node ./scripts/verify-public-build.mjs",
     "lint": "eslint .",
     "preview": "vite preview"
diff --git a/frontend/scripts/verify-router-lazy.mjs b/frontend/scripts/verify-router-lazy.mjs
new file mode 100644
index 0000000..ff7f704
--- /dev/null
+++ b/frontend/scripts/verify-router-lazy.mjs
@@ -0,0 +1,70 @@
+import { readFile } from 'node:fs/promises';
+import path from 'node:path';
+import process from 'node:process';
+import { pathToFileURL } from 'node:url';
+
+/**
+ * 校验路由表里每个 renderLazyComponent(X) 用到的组件 X 都在同文件里
+ * 用 `const X = lazy(() => import(...))` 声明过。
+ *
+ * 为什么要这个检查（2026-10-22 生产事故）：
+ *   PR #74 新增「缺货补货监控」时，router/index.jsx 里写了
+ *   `element: renderLazyComponent(BinReplenishMonitor)` 却漏了 lazy 声明。
+ *   这行在模块顶层执行 → 加载即抛 `ReferenceError: BinReplenishMonitor is not defined`
+ *   → 整个 React 应用挂掉、**全站白屏，连登录页都渲染不出来**。
+ *   而 `vite build` 完全能构建成功（未声明标识符在 JS 里是合法语法），
+ *   所以必须在构建期用静态扫描拦住。
+ */
+export async function verifyRouterLazy(routerPath = path.resolve(process.cwd(), 'src/router/index.jsx')) {
+  const source = await readFile(routerPath, 'utf8');
+
+  const used = new Set();
+  for (const match of source.matchAll(/renderLazyComponent\s*\(\s*([A-Za-z_$][\w$]*)/g)) {
+    used.add(match[1]);
+  }
+
+  const declared = new Set();
+  for (const match of source.matchAll(/const\s+([A-Za-z_$][\w$]*)\s*=\s*lazy\s*\(/g)) {
+    declared.add(match[1]);
+  }
+
+  const missing = [...used].filter((name) => !declared.has(name)).sort();
+
+  if (missing.length > 0) {
+    const lines = missing.map((name) => {
+      const idx = source.indexOf(`renderLazyComponent(${name}`);
+      const line = idx === -1 ? '?' : source.slice(0, idx).split('\n').length;
+      return `  - ${name}  (router/index.jsx:${line} 使用，缺少 const ${name} = lazy(() => import('...')) 声明)`;
+    });
+    throw new Error(
+      'router/index.jsx 有组件被 renderLazyComponent 使用但未声明为 lazy，' +
+        '这会导致运行时 ReferenceError 并让整站白屏：\n' +
+        lines.join('\n'),
+    );
+  }
+
+  return { routerPath, used: [...used].sort(), declared: [...declared].sort() };
+}
+
+async function main() {
+  const routerArg = process.argv[2];
+  const routerPath = routerArg
+    ? path.resolve(process.cwd(), routerArg)
+    : path.resolve(process.cwd(), 'src/router/index.jsx');
+  const result = await verifyRouterLazy(routerPath);
+  process.stdout.write(
+    `Verified router lazy declarations: ${result.used.length} used, ${result.declared.length} declared ` +
+      `(${path.relative(process.cwd(), result.routerPath)})\n`,
+  );
+}
+
+const isDirectExecution = process.argv[1]
+  ? pathToFileURL(path.resolve(process.argv[1])).href === import.meta.url
+  : false;
+
+if (isDirectExecution) {
+  main().catch((error) => {
+    process.stderr.write(`${error.message}\n`);
+    process.exitCode = 1;
+  });
+}
diff --git a/frontend/src/router/index.jsx b/frontend/src/router/index.jsx
index a6ecd7d..6a023db 100644
--- a/frontend/src/router/index.jsx
+++ b/frontend/src/router/index.jsx
@@ -25,6 +25,10 @@ const DailyInventory = lazy(() => import('../pages/DailyInventory'));
 const StockSalesAnalysis = lazy(() => import('../pages/StockSalesAnalysis'));
 const PickingBinSalesAnalysis = lazy(() => import('../pages/PickingBinSalesAnalysis'));
 const ReturnsInventoryMonitor = lazy(() => import('../pages/ReturnsInventoryWarning/Monitor'));
+// ⚠️ 每个在下面路由表里被 renderLazyComponent(...) 用到的页面都必须先在这里声明。
+//    漏一个 = 模块顶层抛 ReferenceError（xxx is not defined）→ 整个应用白屏、连登录页都进不去。
+//    PR #74 就漏了 BinReplenishMonitor，导致生产 10-22 全站白屏（2026-10-22 修复）。
+const BinReplenishMonitor = lazy(() => import('../pages/BinReplenishMonitor'));
 
 const lazyLoadingElement = <PageLoadingFallback />;