fix: 修复后台文章计数为0 + 分类编辑补全描述字段 + CSP放行外部图片 + 更新关于页描述

- 文章管理：计数请求补 page=1 参数，命中分页接口返回正确的 total
- 分类管理：编辑模式新增描述输入框，保存时一并提交 description
- CSP：img-src 加入 https: 允许加载外部图片
- 关于页：数据存储描述从 JSON 文件更正为 SQLite 数据库
- Footer：添加 ICP 备案号

src/app/posts/[slug]/page.tsx

@@ -1,29 +1,76 @@
+import type { Metadata } from "next";
 import { notFound } from "next/navigation";
-import { posts } from "@/data/posts";
+import { getPostBySlug, getPublishedPosts } from "@/lib/store";
 import PostContent from "@/components/PostContent";
 
+const SITE_URL = process.env.NEXT_PUBLIC_SITE_URL || "https://asui.xyz";
+
 export async function generateStaticParams() {
+  const posts = await getPublishedPosts();
   return posts.map((post) => ({ slug: post.slug }));
 }
 
-export async function generateMetadata({ params }: { params: Promise<{ slug: string }> }) {
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ slug: string }>;
+}): Promise<Metadata> {
   const { slug } = await params;
-  const post = posts.find((p) => p.slug === slug);
+  const post = await getPostBySlug(slug);
   if (!post) return {};
+
+  const url = `${SITE_URL}/posts/${post.slug}`;
   return {
     title: post.title,
     description: post.excerpt,
+    alternates: { canonical: url },
+    openGraph: {
+      title: post.title,
+      description: post.excerpt,
+      url,
+      type: "article",
+      publishedTime: post.date,
+      authors: ["胡旭"],
+      tags: post.tags,
+      siteName: "随 · asui.xyz",
+      locale: "zh_CN",
+    },
+    twitter: {
+      card: "summary_large_image",
+      title: post.title,
+      description: post.excerpt,
+    },
   };
 }
 
 export default async function PostPage({ params }: { params: Promise<{ slug: string }> }) {
   const { slug } = await params;
-  const post = posts.find((p) => p.slug === slug);
+  const post = await getPostBySlug(slug);
   if (!post) notFound();
 
-  const currentIndex = posts.findIndex((p) => p.slug === slug);
-  const prevPost = currentIndex > 0 ? posts[currentIndex - 1] : null;
-  const nextPost = currentIndex < posts.length - 1 ? posts[currentIndex + 1] : null;
+  const all = await getPublishedPosts();
+  const currentIndex = all.findIndex((p) => p.slug === slug);
+  const prevPost = currentIndex > 0 ? all[currentIndex - 1] : null;
+  const nextPost = currentIndex < all.length - 1 ? all[currentIndex + 1] : null;
 
-  return <PostContent post={post} prevPost={prevPost} nextPost={nextPost} />;
+  // BlogPosting 结构化数据，利于搜索引擎富摘要
+  const jsonLd = {
+    "@context": "https://schema.org",
+    "@type": "BlogPosting",
+    headline: post.title,
+    description: post.excerpt,
+    datePublished: post.date,
+    dateModified: post.updatedAt,
+    author: { "@type": "Person", name: "胡旭", url: SITE_URL },
+    publisher: { "@type": "Person", name: "胡旭" },
+    mainEntityOfPage: `${SITE_URL}/posts/${post.slug}`,
+    keywords: post.tags.join(", "),
+  };
+
+  return (
+    <>
+      <script type="application/ld+json" dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd) }} />
+      <PostContent post={post} prevPost={prevPost} nextPost={nextPost} />
+    </>
+  );
 }