perf : improve more

app/robots.ts

@@ -0,0 +1,11 @@
+import type { MetadataRoute } from "next";
+
+export default function robots(): MetadataRoute.Robots {
+  return {
+    rules: {
+      userAgent: "*",
+      allow: "/",
+      disallow: ["/admin", "/api", "/register"],
+    },
+  };
+}

components/public/structured-directory.tsx

@@ -70,7 +70,7 @@ export function StructuredDirectory({ guides }: { guides: GuideCard[] }) {
                     src={guide.coverUrl}
                     alt={`ไกด์ ${guide.name}`}
                     fill
-                    preload={index === 0}
+                    fetchPriority={index === 0 ? "high" : undefined}
                     sizes="(min-width: 1024px) 33vw, (min-width: 640px) 50vw, 100vw"
                     className="object-cover"
                   />

tests/public-performance.test.ts

@@ -2,6 +2,8 @@ import { readFile } from "node:fs/promises";
 
 import { describe, expect, it } from "vitest";
 
+import robots from "@/app/robots";
+
 async function repositoryFile(path: string): Promise<string> {
   return readFile(new URL(`../${path}`, import.meta.url), "utf8");
 }
@@ -27,11 +29,24 @@ describe("public rendering performance", () => {
     expect(header).toContain("<AdminEditLink");
   });
 
-  it("preloads only the first directory cover", async () => {
+  it("gives only the first directory cover high fetch priority", async () => {
     const directory = await repositoryFile(
       "components/public/structured-directory.tsx",
     );
 
-    expect(directory).toContain("preload={index === 0}");
+    expect(directory).toContain(
+      'fetchPriority={index === 0 ? "high" : undefined}',
+    );
+    expect(directory).not.toContain("preload={index === 0}");
+  });
+
+  it("publishes a public-only crawler policy", () => {
+    expect(robots()).toEqual({
+      rules: {
+        userAgent: "*",
+        allow: "/",
+        disallow: ["/admin", "/api", "/register"],
+      },
+    });
   });
 });