feat: 顶栏显示当前页名,去掉独立标题行;Logo回首页/页名回顶部

- 新增 PageTitleContext:页面上报标题,顶栏 brand 位显示当前页名(全部资料/
  热门资料/最新/官方/分类名/搜索/我的收藏),未上报则回退品牌名
- AssetStreamPage、Favorites 上报标题;移除资料流内单独的标题行,省出空间
- 顶栏拆分点击:Logo→首页(首页则回顶部);页名文字→回到当前页顶部

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/AssetStreamPage.tsx

@@ -1,5 +1,6 @@
 import type { PostScope } from "../types/post";
 import { MessageStream } from "./messageStream/MessageStream";
+import { useSetPageTitle } from "./PageTitleContext";
 
 type AssetStreamPageProps = {
   title: string;
@@ -7,9 +8,12 @@ type AssetStreamPageProps = {
 };
 
 export function AssetStreamPage({ title, scope }: AssetStreamPageProps) {
+  // Show the page name in the global header instead of a separate title row,
+  // saving vertical space.
+  useSetPageTitle(title);
   return (
     <section>
-      <MessageStream scope={scope} title={title} />
+      <MessageStream scope={scope} />
     </section>
   );
 }