feat(ssr): 帖子页全量 SSR——作者卡/目录首帧服务端渲染，消除冗余首屏请求

- 帖子快照携带作者主页资料与统计（authorProfile/authorStats），
  SSR 端与客户端预热均取 /api/users/:id；PostAuthorCard 首帧直接渲染，
  不再挂载后请求，统计数字不再显示 — 占位
- MainLayout 首帧从已 seed 的帖子快照派生右栏 outline（作者卡+文章目录），
  修复 outline 仅靠 effect 上报导致 SSR 不渲染右栏的问题
- 壳层首屏请求门控：useAuth 有种子跳过 /api/me、branding 缓存命中不重拉、
  侧栏三个区块首屏用 seed 缓存、未读数首屏跳过即时请求（轮询/事件刷新保留）
- serverDom(linkedom) 修复：DOMParser 片段包裹、属性顺序、SVG 自闭合展开
- 验证：首页与帖子页 hydration 后仅剩 pageview 上报，0 hydration 错误

frontend/src/pages/PostDetailPage.tsx

@@ -33,7 +33,7 @@ import {
 } from '@/components/ui/dialog';
 import { notify } from '@/lib/notify';
 import { api } from '../api/client';
-import type { PostItem, Comment, ReportReason, PollView, PostLotteryView } from '../api/types';
+import type { PostItem, Comment, PollView, PostLotteryView, ReportReason } from '../api/types';
 import { REPORT_REASON_OPTIONS } from '../utils/report';
 import CommentThreadList from '../components/CommentThreadList';
 import CommentBox, { type CommentSubmitData } from '../components/CommentBox';
@@ -48,7 +48,7 @@ import ArticleOutline from '../components/ArticleOutline';
 import { useAuth } from '../hooks/useAuth';
 import { joinSEOKeywords, usePageSEO } from '../hooks/usePageSEO';
 import { getCachedSiteBranding } from '../hooks/useSiteBranding';
-import { formatDateTime, isTimeDiffSignificant } from '../utils/content';
+import { formatDateTime } from '../utils/content';
 import { collectCommentSubtreeIds } from '../utils/comment';
 import { loadMyCommentIds } from '../utils/guest';
 import { clearAllFeedCache, PAGE_FORCE_REFRESH_EVENT } from '../utils/feedCache';
@@ -56,6 +56,7 @@ import { PAGE_SOFT_REFRESH_COMMIT_EVENT } from '../utils/softRefresh';
 import { deleteSessionSnapshot, getSessionSnapshot, setSessionSnapshot } from '../utils/sessionPageCache';
 import { loginPath } from '../utils/authRedirect';
 import { excerptFromHTML, firstImageFromHTML } from '../utils/seoText';
+import { buildPostDetailSnapshot, postDetailCacheKey, type PostDetailSnapshot } from '../utils/homeBoot';
 import { canonicalRedirectPath, parsePermalinkID, postPath } from '../utils/permalink';
 import { useForumLimits } from '../hooks/useForumLimits';
 import type { LayoutCtx } from '../layouts/MainLayout';
@@ -64,26 +65,6 @@ import { renderPostContentHtml } from '../utils/postContent';
 import { InFlowSiteFooter } from '../components/SiteFooter';
 import NotFoundPage from './NotFoundPage';
 
-type PostDetailSnapshot = {
-  post: PostItem;
-  comments: Comment[];
-  poll: PollView | null;
-  lottery: PostLotteryView | null;
-  liked: boolean;
-  favorited: boolean;
-  canEdit: boolean;
-  isEdited: boolean;
-  editBlockReason: string;
-  editWindowHours: number;
-  bountyCanRefund: boolean;
-  bountyRefundBlockReason: string;
-  bountyEligibleReplyCount: number;
-};
-
-function postDetailCacheKey(id: number) {
-  return `post:${id}`;
-}
-
 /** 格式化剩余可编辑时间 */
 function formatEditRemaining(createdAt: string, windowHours: number): string {
   if (windowHours <= 0) return '';
@@ -143,6 +124,8 @@ export default function PostDetailPage() {
   const [bountyCanRefund, setBountyCanRefund] = useState(initialSnap?.bountyCanRefund ?? true);
   const [bountyRefundBlockReason, setBountyRefundBlockReason] = useState(initialSnap?.bountyRefundBlockReason ?? '');
   const [bountyEligibleReplyCount, setBountyEligibleReplyCount] = useState(initialSnap?.bountyEligibleReplyCount ?? 0);
+  const [authorProfile, setAuthorProfile] = useState<PostDetailSnapshot['authorProfile']>(initialSnap?.authorProfile ?? null);
+  const [authorStats, setAuthorStats] = useState<PostDetailSnapshot['authorStats']>(initialSnap?.authorStats ?? null);
 
   const commentSectionRef = useRef<HTMLDivElement>(null);
   const commentBoxRef = useRef<HTMLDivElement>(null);
@@ -206,9 +189,11 @@ export default function PostDetailPage() {
       author: post.user ?? null,
       publishedAt: post.created_at,
       viewCount: post.view_count,
+      authorProfile,
+      authorStats,
     });
     return () => setPostOutline(null);
-  }, [headings, loading, post, setPostOutline]);
+  }, [headings, loading, post, authorProfile, authorStats, setPostOutline]);
 
   const loadSeq = useRef(0);
   const detailPath = postPath(postId, limits);
@@ -226,6 +211,8 @@ export default function PostDetailPage() {
     setBountyCanRefund(snap.bountyCanRefund);
     setBountyRefundBlockReason(snap.bountyRefundBlockReason);
     setBountyEligibleReplyCount(snap.bountyEligibleReplyCount);
+    setAuthorProfile(snap.authorProfile ?? null);
+    setAuthorStats(snap.authorStats ?? null);
     setComments(snap.comments);
     // POP（后退/前进）不干预，交给浏览器原生恢复；
     // PUSH 换帖 / 强制刷新是「换新内容」场景，文档滚动置顶
@@ -273,21 +260,11 @@ export default function PostDetailPage() {
         ]);
         if (seq !== loadSeq.current) return;
         const commentsList = Array.isArray(comm.comments) ? comm.comments : [];
-        const snap: PostDetailSnapshot = {
-          post: detail.post,
-          comments: commentsList,
-          poll: detail.poll ?? null,
-          lottery: detail.lottery ?? null,
-          liked: detail.liked,
-          favorited: detail.favorited,
-          canEdit: detail.can_edit ?? false,
-          isEdited: detail.is_edited ?? isTimeDiffSignificant(detail.post.created_at, detail.post.updated_at ?? detail.post.created_at),
-          editBlockReason: detail.edit_block_reason ?? '',
-          editWindowHours: detail.post_edit_window_hours ?? 0,
-          bountyCanRefund: detail.bounty_can_refund ?? true,
-          bountyRefundBlockReason: detail.bounty_refund_block_reason ?? '',
-          bountyEligibleReplyCount: detail.bounty_eligible_reply_count ?? 0,
-        };
+        // 作者主页资料一并拉取（右栏作者卡首帧完整；失败降级为卡片自行拉取）
+        const authorResp = detail.post.user_id
+          ? await api.userProfile(detail.post.user_id).catch(() => null)
+          : null;
+        const snap = buildPostDetailSnapshot(detail, commentsList, authorResp);
         setSessionSnapshot(postDetailCacheKey(postId), snap);
         applySnapshot(snap, { restoreScroll: false });
         void refresh();
@@ -335,11 +312,14 @@ export default function PostDetailPage() {
       bountyCanRefund,
       bountyRefundBlockReason,
       bountyEligibleReplyCount,
+      authorProfile,
+      authorStats,
+      scrollTop: 0,
     });
   }, [
     post, comments, poll, lottery, liked, favorited, canEdit, isEdited,
     editBlockReason, editWindowHours, bountyCanRefund, bountyRefundBlockReason,
-    bountyEligibleReplyCount, postId, loading,
+    bountyEligibleReplyCount, authorProfile, authorStats, postId, loading,
   ]);
 
   const reloadComments = useCallback(async () => {