feat(web): 前端共享基础(focusRing/proseBody/text-2xs + useBodyScrollLock + Toast撤销 + error/not-found/loading路由边界)

apps/web/lib/ui/useBodyScrollLock.ts

@@ -0,0 +1,20 @@
+"use client";
+
+import { useEffect } from "react";
+
+// 弹层（Drawer / CommandPalette / Modal）打开时锁定 body 滚动，关闭后恢复原值。
+// SSR 守卫：服务端无 document，直接跳过。
+export function useBodyScrollLock(active: boolean): void {
+  useEffect(() => {
+    if (!active) return;
+    if (typeof document === "undefined") return;
+
+    const { body } = document;
+    const previousOverflow = body.style.overflow;
+    body.style.overflow = "hidden";
+
+    return () => {
+      body.style.overflow = previousOverflow;
+    };
+  }, [active]);
+}