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]/edit/page.tsx

@@ -2,6 +2,8 @@
 
 import { useState, useEffect } from "react";
 import { useRouter } from "next/navigation";
+import Link from "next/link";
+import { ChevronRight } from "lucide-react";
 import { fetchPostDetail, apiMe, apiUpdatePost, type Post, type User } from "@/lib/api";
 
 interface EditPageProps {
@@ -19,13 +21,11 @@ export default function EditPostPage({ params }: EditPageProps) {
   const [error, setError] = useState("");
   const [checking, setChecking] = useState(true);
 
-  // params 是 Promise，需要解包
   const [id, setId] = useState("");
   useEffect(() => {
     params.then((p) => setId(p.id));
   }, [params]);
 
-  // 加载帖子 + 校验权限
   useEffect(() => {
     if (!id) return;
     Promise.all([fetchPostDetail(id), apiMe()])
@@ -36,7 +36,6 @@ export default function EditPostPage({ params }: EditPageProps) {
         setTags(postData.post.tags || "");
         const u = meData.user;
         setUser(u || null);
-        // 非作者且非管理员 → 跳转
         if (!u || (u.id !== postData.post.user.id && u.role !== "admin")) {
           router.push(`/post/${id}`);
         }
@@ -64,8 +63,8 @@ export default function EditPostPage({ params }: EditPageProps) {
 
   if (checking) {
     return (
-      <div className="max-w-3xl mx-auto mt-12 text-center" style={{ color: "var(--text-secondary)" }}>
-        加载中...
+      <div className="max-w-3xl mx-auto text-center py-20">
+        <p className="meta">正在加载帖子…</p>
       </div>
     );
   }
@@ -74,59 +73,71 @@ export default function EditPostPage({ params }: EditPageProps) {
 
   return (
     <div className="max-w-3xl mx-auto">
-      <h1 className="text-2xl font-bold mb-6">编辑帖子</h1>
-      <form onSubmit={handleSubmit} className="space-y-4">
-        {error && (
-          <div className="p-3 rounded-lg bg-red-50 text-red-600 text-sm">{error}</div>
-        )}
+      <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={`/post/${post.id}`} className="hover:text-[var(--accent)] transition-colors truncate max-w-[12rem]">
+          帖子详情
+        </Link>
+        <ChevronRight size={13} />
+        <span style={{ color: "var(--accent)" }}>编辑</span>
+      </nav>
+
+      <div className="mb-7">
+        <h1 className="text-[26px] sm:text-[30px] font-extrabold tracking-tight" style={{ color: "var(--ink)" }}>
+          编辑帖子
+        </h1>
+      </div>
+
+      <form onSubmit={handleSubmit} className="panel p-5 sm:p-7 space-y-5">
+        {error && <div className="alert-error">{error}</div>}
+
         <div>
-          <label className="block text-sm mb-1" style={{ color: "var(--text-secondary)" }}>标题</label>
+          <label className="field-label">标题</label>
           <input
             type="text"
             value={title}
             onChange={(e) => setTitle(e.target.value)}
             required
             maxLength={256}
-            className="w-full px-3 py-2 rounded-lg border"
-            style={{ borderColor: "var(--border)", background: "var(--bg)", color: "var(--text)" }}
+            className="field"
           />
         </div>
+
         <div>
-          <label className="block text-sm mb-1" style={{ color: "var(--text-secondary)" }}>标签（逗号分隔，可选）</label>
+          <label className="field-label">标签（逗号分隔，可选）</label>
           <input
             type="text"
             value={tags}
             onChange={(e) => setTags(e.target.value)}
-            placeholder="例如：技术,Go"
-            className="w-full px-3 py-2 rounded-lg border"
-            style={{ borderColor: "var(--border)", background: "var(--bg)", color: "var(--text)" }}
+            placeholder="Go, PostgreSQL, 架构"
+            className="field"
           />
         </div>
+
         <div>
-          <label className="block text-sm mb-1" style={{ color: "var(--text-secondary)" }}>内容（支持 Markdown）</label>
+          <label className="field-label">正文（支持 Markdown）</label>
           <textarea
             value={content}
             onChange={(e) => setContent(e.target.value)}
             required
-            rows={12}
-            className="w-full px-3 py-2 rounded-lg border resize-y font-mono"
-            style={{ borderColor: "var(--border)", background: "var(--bg)", color: "var(--text)" }}
+            rows={14}
+            className="field"
           />
         </div>
-        <div className="flex gap-3">
+
+        <div className="flex gap-3 pt-2">
           <button
             type="submit"
             disabled={loading || !title.trim() || !content.trim()}
-            className="px-6 py-2 rounded-lg text-white disabled:opacity-50"
-            style={{ background: "var(--primary)" }}
+            className="btn btn-primary"
           >
             {loading ? "保存中..." : "保存修改"}
           </button>
           <button
             type="button"
             onClick={() => router.push(`/post/${post.id}`)}
-            className="px-6 py-2 rounded-lg"
-            style={{ background: "var(--bg-secondary)", color: "var(--text)" }}
+            className="btn btn-line"
           >
             取消
           </button>