feat: 帖子收藏与用户关注

- 新增收藏功能：favorite 服务与 handler、FavoriteButton 组件
- 新增关注功能：follow 服务与 handler、FollowButton 组件
- 用户主页适配关注/粉丝与收藏展示
- flash 消息工具、广告与侧边栏组件微调

frontend/components/PostRow.tsx

@@ -6,7 +6,6 @@ import { getPublicSettingsCached } from "@/lib/serverData";
 import { normalizePostType, postTypeLabel, typeStatusLabel, typeStatusClass } from "@/lib/postMeta";
 import LikeButton from "./LikeButton";
 import Avatar from "./Avatar";
-import BadgeChip from "./BadgeChip";
 import { IconComment, IconEye } from "./Icons";
 
 /**
@@ -104,9 +103,6 @@ export default async function PostRow({
           >
             {authorName}
           </Link>
-          {(post.user.badges ?? []).slice(0, 2).map((ub) => (
-            <BadgeChip key={ub.id} badge={ub.badge} />
-          ))}
           <span aria-hidden>·</span>
           <span className="tabular-nums">{formatRelative(post.created_at)}</span>
           {replied && (