feat(ssr): 真 SSR 收尾——干净 hydration 与浏览器原生滚动恢复

- 修复 onRenderClient 引入 serverClient 导致浏览器 process is not defined：
  抽出双端安全的 ssr/feedSeed.ts 作为唯一数据播种入口，serverClient 加 SSR 守卫
- 修复 React 19 Fizz Suspense Outlining：Suspense 边界从布局 Outlet 下移到
  各懒加载路由，SSR 输出不再出现 <!--$?--> / $RB / template 探针标记
- 修复窄屏 React #418 hydration 致命错误：useMediaQuery 首帧恒 false，
  useLayoutEffect 绘制前同步真实值；主题改 cookie 存储供 SSR 直出，
  head 内联防闪烁/缩放脚本移除（缩放锁改为客户端 zoomGuard 模块）
- 清理假 SSR 残留：删除 StaticFeedList 镜像组件、SSR 图标生成脚本、
  探针与死代码；列表接口裁剪正文，仅下发 excerpt/first_image
- Feed 与帖子详情改为窗口滚动（app-shell--doc-scroll）：删除虚拟列表、
  自研滚动快照与全局滚轮 hack；F5/前进后退滚动位置全部交给浏览器原生
  历史恢复，HTML 响应头 no-cache 配合；锚点/楼层用 scrollIntoView +
  scroll-margin-top 适配 sticky 顶栏

frontend/renderer/+onRenderClient.tsx

@@ -3,9 +3,10 @@ import type { ComponentType } from 'react';
 import { hydrateRoot, createRoot } from 'react-dom/client';
 import type { PageContextClient } from 'vike/types';
 import { applyTheme, getStoredTheme } from '../src/utils/theme';
+import { installZoomGuard } from '../src/utils/zoomGuard';
 import { beginHomeHydrate } from '../src/utils/homeHydrate';
 import { reloadForStaleChunk } from '../src/utils/chunkLoad';
-import { seedFeedData, type FeedData } from '../src/ssr/feedData';
+import { seedFeedData, type FeedData } from '../src/ssr/feedSeed';
 import { ensureColdBootReady, isMainLayoutPath } from '../src/utils/prefetchRoute';
 
 export { onRenderClient };
@@ -40,6 +41,7 @@ function waitForStylesheets(): Promise<void> {
 
 async function onRenderClient(pageContext: PageContextClient) {
   applyTheme(getStoredTheme());
+  installZoomGuard();
   // hydrate 前把 +data 结果 seed 进客户端缓存（与服务端渲染前 seed 同构，保证首帧一致）
   if (pageContext.isHydration) {
     seedFeedData((pageContext as { data?: FeedData }).data);
@@ -54,6 +56,16 @@ async function onRenderClient(pageContext: PageContextClient) {
   const el = document.getElementById('root');
   if (!el) return;
 
+  // 有 SSR 正文 → hydrate 接管同一 DOM（首帧数据已由 +data seed，无需冷启动预热）；
+  // SPA 壳 / SSR 降级空壳 → createRoot 挂载，挂载前先冷启动预热，避免空白首帧
+  const hydrating = pageContext.isHydration && el.innerHTML.trim() !== '';
+
+  // 仅非 hydrate 路径需要冷启动：SSR 页 seed 已灌入缓存，冷启动只会重复请求并阻塞 hydrate
+  if (!hydrating && isMainLayoutPath(window.location.pathname)) {
+    const path = `${window.location.pathname}${window.location.search}`;
+    await ensureColdBootReady(path);
+  }
+
   await waitForStylesheets();
   try {
     if (document.fonts?.ready) await document.fonts.ready;
@@ -61,13 +73,6 @@ async function onRenderClient(pageContext: PageContextClient) {
     /* ignore */
   }
 
-  const path = `${window.location.pathname}${window.location.search}`;
-  if (isMainLayoutPath(window.location.pathname)) {
-    await ensureColdBootReady(path);
-  }
-
-  // 有 SSR 正文 → hydrate 接管同一 DOM（首帧 hydrate 同构变体）；SPA 壳 → 整树挂载
-  const hydrating = pageContext.isHydration && el.innerHTML.trim() !== '';
   if (hydrating) beginHomeHydrate();
 
   const Page = pageContext.Page as PageComponent;

frontend/renderer/+onRenderHtml.tsx

@@ -5,9 +5,11 @@ import type { PageContextServer } from 'vike/types';
 import { createHomeStore } from '../src/store/homeStore';
 import { createRequestScope } from '../src/ssr/scopeTypes';
 import { runWithScope } from '../src/ssr/scope';
-import { seedFeedData, type FeedData } from '../src/ssr/feedData';
+import { seedFeedData, type FeedData } from '../src/ssr/feedSeed';
 import { renderHeadTags } from '../src/ssr/head';
 import { installServerDom } from '../src/ssr/serverDom';
+import { readThemeFromCookie } from '../src/utils/theme';
+import { createSsrApp } from '../src/App';
 
 // 服务端 DOM polyfill：内容处理依赖 DOMParser/document，须在渲染前安装
 installServerDom();
@@ -16,14 +18,6 @@ export { onRenderHtml };
 
 type PageComponent = ComponentType<{ url?: string }>;
 
-/** 首帧主题脚本（localStorage j13-theme），与旧 index.html 保持一致 */
-const THEME_INIT_SCRIPT
-  = "(function(){var t=localStorage.getItem('j13-theme')||'light';document.documentElement.classList.toggle('dark',t==='dark');document.documentElement.style.colorScheme=t;})();";
-
-/** 锁死手机/平板双指与手势缩放；头像裁剪 / 图片灯箱放行 pinch */
-const ZOOM_BLOCK_SCRIPT
-  = "(function(){function inZoomAllowArea(target){return !!(target&&target.closest&&target.closest('.avatar-crop-stage, .image-lightbox'));}function blockGesture(e){if(inZoomAllowArea(e.target))return;if(e.cancelable)e.preventDefault();}function blockMultiTouch(e){if(e.touches&&e.touches.length>1){if(inZoomAllowArea(e.target))return;if(e.cancelable)e.preventDefault();}}document.addEventListener('gesturestart',blockGesture,{passive:false});document.addEventListener('gesturechange',blockGesture,{passive:false});document.addEventListener('gestureend',blockGesture,{passive:false});document.addEventListener('touchstart',blockMultiTouch,{passive:false});document.addEventListener('touchmove',blockMultiTouch,{passive:false});})();";
-
 /** 等 lazy 页面全部渲染完成（allReady）后缓冲为完整 HTML，首字节语义与旧 Go 文档级 SSR 一致 */
 async function renderPageToString(element: ReactElement): Promise<string> {
   const stream = await renderToReadableStream(element, {
@@ -47,10 +41,13 @@ async function onRenderHtml(pageContext: PageContextServer) {
     const { pathname, searchOriginal } = pageContext.urlParsed;
     const url = pathname + (searchOriginal ?? '');
     try {
-      pageHtml = await runWithScope(scope, () => {
+      pageHtml = await runWithScope(scope, async () => {
         // 渲染前把 +data 取回的数据 seed 进请求作用域（缓存层按 scope 隔离）
         seedFeedData(data);
-        return renderPageToString(<Page url={url} />);
+        // 官方 SSR 路径：await 首导航后 StaticRouterProvider 同步渲染（避免 RouterProvider suspend
+        // 导致内容落入 <div hidden>，禁 JS 爬虫不可见）
+        const app = await createSsrApp(url);
+        return renderPageToString(app);
       });
     } catch (err) {
       console.error('[j13] SSR 渲染失败，降级 SPA 壳:', err);
@@ -60,15 +57,19 @@ async function onRenderHtml(pageContext: PageContextServer) {
 
   const headTags = renderHeadTags(data?.head);
 
+  // 主题从请求 Cookie 读取，首帧直接渲染到 <html> 上（深色用户无白屏闪烁，无需内联脚本）
+  // headersOriginal 经 Vike 归一化为 pageContext.headers（键全小写）
+  const cookieHeader = (pageContext as { headers?: Record<string, string> | null }).headers?.cookie;
+  const dark = readThemeFromCookie(cookieHeader) === 'dark';
+  const htmlAttrs = dark ? ' class="dark" style="color-scheme:dark"' : '';
+
   // 404/301 等状态码由 Vike abort 机制（throw render/redirect）原生处理
   return escapeInject`<!DOCTYPE html>
-<html lang="zh-CN">
+<html lang="zh-CN"${dangerouslySkipEscape(htmlAttrs)}>
   <head>
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
     ${dangerouslySkipEscape(headTags)}
-    <script>${dangerouslySkipEscape(THEME_INIT_SCRIPT)}</script>
-    <script>${dangerouslySkipEscape(ZOOM_BLOCK_SCRIPT)}</script>
   </head>
   <body>
     <div id="root">${dangerouslySkipEscape(pageHtml)}</div>