feat: 新增大量社区功能与基础组件，优化站点整体体验

- 新增事件总线式toast通知系统
- 新增头像、阅读进度、404/500错误页等基础组件
- 重构页脚、布局、分页、点赞按钮等现有组件
- 新增用户个人页、通知中心、帖子编辑/发布/置顶/推荐管理功能
- 优化登录注册页面样式与交互
- 修复路径类型文件引用，更新站点元信息与字体配置

frontend/app/post/[id]/page.tsx

@@ -1,4 +1,4 @@
-import { Metadata } from "next";
+import type { Metadata } from "next";
 import Link from "next/link";
 import { cookies } from "next/headers";
 import ReactMarkdown from "react-markdown";
@@ -6,6 +6,10 @@ import { fetchPostDetail, fetchComments } from "@/lib/api";
 import CommentSection from "@/components/CommentSection";
 import PostActions from "@/components/PostActions";
 import LikeButton from "@/components/LikeButton";
+import ReadingProgress from "@/components/ReadingProgress";
+import Avatar from "@/components/Avatar";
+import { IconComment, IconEye } from "@/components/Icons";
+import { ChevronRight } from "lucide-react";
 
 interface PageProps {
   params: Promise<{ id: string }>;
@@ -16,7 +20,7 @@ export async function generateMetadata({ params }: PageProps): Promise<Metadata>
   try {
     const { post } = await fetchPostDetail(id);
     return {
-      title: `${post.title} - 姜十三论坛`,
+      title: post.title,
       description: post.content.slice(0, 160),
       openGraph: {
         title: post.title,
@@ -25,7 +29,7 @@ export async function generateMetadata({ params }: PageProps): Promise<Metadata>
       },
     };
   } catch {
-    return { title: "帖子不存在 - 姜十三论坛" };
+    return { title: "帖子不存在" };
   }
 }
 
@@ -42,10 +46,7 @@ export default async function PostDetailPage({ params }: PageProps) {
     articleBody: post.content,
     datePublished: post.created_at,
     dateModified: post.updated_at,
-    author: {
-      "@type": "Person",
-      name: post.user.nickname,
-    },
+    author: { "@type": "Person", name: post.user.nickname },
     commentCount: post.comment_count,
     interactionStatistic: {
       "@type": "InteractionCounter",
@@ -56,42 +57,79 @@ export default async function PostDetailPage({ params }: PageProps) {
 
   return (
     <article className="max-w-3xl mx-auto">
-      <script
-        type="application/ld+json"
-        dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd) }}
-      />
+      <ReadingProgress />
+      <script type="application/ld+json" dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd) }} />
 
-      <nav className="text-sm mb-4" style={{ color: "var(--text-secondary)" }}>
-        <Link href="/" className="hover:underline">首页</Link>
-        <span className="mx-2">/</span>
-        <Link href={`/board/${post.board.id}`} className="hover:underline">{post.board.name}</Link>
+      <nav className="meta mb-5 flex items-center gap-1.5 flex-wrap text-[13px]">
+        <Link href="/" className="hover:text-[var(--accent)] transition-colors">首页</Link>
+        <ChevronRight size={13} />
+        <Link href={`/board/${post.board.id}`} className="hover:text-[var(--accent)] transition-colors">
+          {post.board.name}
+        </Link>
       </nav>
 
-      <div className="flex items-center gap-2 mb-3">
-        {post.pinned > 0 && (
-          <span className="text-xs px-2 py-0.5 rounded bg-amber-100 text-amber-700">置顶</span>
-        )}
-        {post.recommended && (
-          <span className="text-xs px-2 py-0.5 rounded bg-rose-100 text-rose-700">推荐</span>
-        )}
-      </div>
-      <h1 className="text-3xl font-bold mb-4">{post.title}</h1>
+      <div className="panel p-6 sm:p-9">
+        <header className="mb-7">
+          <div className="flex items-center gap-2 mb-4 flex-wrap">
+            {post.pinned > 0 && <span className="badge-pin">置顶</span>}
+            {post.recommended && <span className="badge-rec">推荐</span>}
+            <Link href={`/board/${post.board.id}`} className="chip">
+              {post.board.name}
+            </Link>
+          </div>
+          <h1 className="text-[26px] sm:text-[34px] font-extrabold leading-tight tracking-tight mb-6" style={{ color: "var(--ink)" }}>
+            {post.title}
+          </h1>
 
-      <div className="flex items-center justify-between gap-4 mb-6 pb-4 border-b" style={{ borderColor: "var(--border)" }}>
-        <div className="flex items-center gap-4" style={{ color: "var(--text-secondary)" }}>
-          <Link href={`/u/${post.user.id}`} className="hover:underline" style={{ color: "var(--primary)" }}>
-            {post.user.nickname}
-          </Link>
-          <span>{new Date(post.created_at).toLocaleString("zh-CN")}</span>
-          <span>👁 {post.view_count}</span>
-          <span>💬 {post.comment_count}</span>
-          <LikeButton postId={id} liked={post.liked} likeCount={post.like_count} />
+          <div
+            className="flex items-center justify-between gap-4 flex-wrap pb-5"
+            style={{ borderBottom: "1px solid var(--line)" }}
+          >
+            <div className="flex items-center gap-4 flex-wrap">
+              <Link
+                href={`/u/${post.user.id}`}
+                className="flex items-center gap-2.5 group"
+              >
+                <Avatar name={post.user.nickname || post.user.username} size={40} />
+                <span className="text-sm font-semibold group-hover:text-[var(--accent)] transition-colors" style={{ color: "var(--ink)" }}>
+                  {post.user.nickname}
+                </span>
+              </Link>
+              <span className="meta">{new Date(post.created_at).toLocaleString("zh-CN")}</span>
+              <span className="inline-flex items-center gap-1.5 meta">
+                <IconEye size={14} /> {post.view_count}
+              </span>
+              <span className="inline-flex items-center gap-1.5 meta">
+                <IconComment size={14} /> {post.comment_count}
+              </span>
+            </div>
+            <div className="flex items-center gap-2">
+              <LikeButton postId={id} liked={post.liked} likeCount={post.like_count} />
+              <PostActions postId={id} authorId={post.user.id} pinned={post.pinned} recommended={post.recommended} />
+            </div>
+          </div>
+        </header>
+
+        {post.tags && (
+          <div className="flex flex-wrap gap-2 mb-7">
+            {[
+              ...new Set(
+                post.tags
+                  .split(",")
+                  .map((t) => t.trim())
+                  .filter(Boolean)
+              ),
+            ].map((t, i) => (
+              <span key={`${t}-${i}`} className="chip">
+                # {t}
+              </span>
+            ))}
+          </div>
+        )}
+
+        <div className="prose-content">
+          <ReactMarkdown>{post.content}</ReactMarkdown>
         </div>
-        <PostActions postId={id} authorId={post.user.id} pinned={post.pinned} recommended={post.recommended} />
-      </div>
-
-      <div className="prose-content mb-8" style={{ color: "var(--text)" }}>
-        <ReactMarkdown>{post.content}</ReactMarkdown>
       </div>
 
       <CommentSection postId={id} comments={comments} />