fix(brand): brand更新不及时的问题

frontend/src/core/brand/provider-client.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useSearchParams } from "next/navigation";
-import { useLayoutEffect } from "react";
+import { useEffect, useRef } from "react";
 
 import { useBrand } from "./provider";
 
@@ -10,25 +10,32 @@ import {
   readStoredBrand,
   resolveBrandSession,
   writeStoredBrand,
+  type Brand,
 } from "./index";
 
 export function BrandSessionInitializer() {
   const searchParams = useSearchParams();
-  const { setBrand } = useBrand();
+  const { brand, setBrand } = useBrand();
+  const prevBrandRef = useRef<Brand>(brand);
 
-  useLayoutEffect(() => {
-    const storedBrand = readStoredBrand(window.sessionStorage);
-    const urlBrand = parseBrandFromSearchParams(
-      new URLSearchParams(searchParams.toString()),
-    );
-    const resolvedBrand = resolveBrandSession({
-      urlBrand,
-      storedBrand,
-    });
+  // 在 render 阶段同步计算，确保每次 searchParams 变化都能感知
+  const storedBrand =
+    typeof window !== "undefined"
+      ? readStoredBrand(window.sessionStorage)
+      : null;
+  const urlBrand = parseBrandFromSearchParams(
+    new URLSearchParams(searchParams.toString()),
+  );
+  const resolvedBrand = resolveBrandSession({ urlBrand, storedBrand });
 
-    writeStoredBrand(window.sessionStorage, resolvedBrand);
-    setBrand(resolvedBrand);
-  }, [searchParams, setBrand]);
+  // 只在品牌确实变化时才写入 sessionStorage 并更新 context
+  useEffect(() => {
+    if (resolvedBrand !== prevBrandRef.current) {
+      prevBrandRef.current = resolvedBrand;
+      writeStoredBrand(window.sessionStorage, resolvedBrand);
+      setBrand(resolvedBrand);
+    }
+  }, [resolvedBrand, setBrand]);
 
   return null;
 }