Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

next.config.ts

@@ -52,15 +52,11 @@ const nextConfig: NextConfig = {
       },
       {
         source: "/assets/(.*)",
-        headers: [
-          { key: "Cache-Control", value: "public, max-age=31536000, immutable" },
-        ],
+        headers: [{ key: "Cache-Control", value: "public, max-age=31536000, immutable" }],
       },
       {
         source: "/images/(.*)",
-        headers: [
-          { key: "Cache-Control", value: "public, max-age=86400" },
-        ],
+        headers: [{ key: "Cache-Control", value: "public, max-age=86400" }],
       },
     ];
   },
@@ -70,4 +66,4 @@ const nextConfig: NextConfig = {
 // src/i18n/request.ts, so URLs and the access-guard middleware stay unchanged.
 const withNextIntl = createNextIntlPlugin("./src/i18n/request.ts");
 
-export default withNextIntl(nextConfig);
+export default withNextIntl(nextConfig);