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

next.config.ts

@@ -1,7 +1,36 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  poweredByHeader: false,
+
+  images: {
+    formats: ["image/avif", "image/webp"],
+  },
+
+  async headers() {
+    return [
+      {
+        source: "/(.*)",
+        headers: [
+          { key: "X-Content-Type-Options", value: "nosniff" },
+          { key: "X-Frame-Options", value: "DENY" },
+          { key: "Referrer-Policy", value: "strict-origin-when-cross-origin" },
+          { key: "Permissions-Policy", value: "camera=(), microphone=(), geolocation=()" },
+          {
+            key: "Content-Security-Policy",
+            value: [
+              "default-src 'self'",
+              "script-src 'self' 'unsafe-inline' 'unsafe-eval'",
+              "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com",
+              "font-src 'self' https://fonts.gstatic.com",
+              "img-src 'self' data: blob: https:",
+              "connect-src 'self'",
+            ].join("; "),
+          },
+        ],
+      },
+    ];
+  },
 };
 
 export default nextConfig;