chore(tooling): modernize Next verification setup

tests/static-export.test.mjs

@@ -0,0 +1,26 @@
+import assert from 'node:assert/strict';
+import { access, readFile } from 'node:fs/promises';
+import path from 'node:path';
+import test from 'node:test';
+
+const exportRoot = path.resolve('out');
+
+test('the production build exports a usable home page', async () => {
+  const indexPath = path.join(exportRoot, 'index.html');
+  const html = await readFile(indexPath, 'utf8');
+
+  assert.match(html, /<!DOCTYPE html>/i);
+  assert.match(html, /<html[^>]*lang=/i);
+
+  const assetPaths = [
+    ...html.matchAll(/(?:src|href)="(\/_next\/static\/[^"?#]+)/g),
+  ].map((match) => match[1]);
+
+  assert.ok(assetPaths.length > 0, 'expected the home page to reference built assets');
+
+  await Promise.all(
+    [...new Set(assetPaths)].map((assetPath) =>
+      access(path.join(exportRoot, assetPath.replace(/^\//, ''))),
+    ),
+  );
+});