build!: upgrade Astro to v5 and related packages

astro.config.ts

@@ -1,9 +1,9 @@
 import { defineConfig } from "astro/config";
-import tailwind from "@astrojs/tailwind";
 import react from "@astrojs/react";
+import sitemap from "@astrojs/sitemap";
+import tailwind from "@astrojs/tailwind";
 import remarkToc from "remark-toc";
 import remarkCollapse from "remark-collapse";
-import sitemap from "@astrojs/sitemap";
 import { SITE } from "./src/config";
 
 // https://astro.build/config
@@ -40,7 +40,4 @@ export default defineConfig({
     },
   },
   scopedStyleStrategy: "where",
-  experimental: {
-    contentLayer: true,
-  },
 });