First commit, phased 1 and 2 created but untested

tests/health.test.js

@@ -0,0 +1,36 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const http = require('node:http');
+const { createApp } = require('../src/app');
+
+function startServer(app) {
+  return new Promise((resolve) => {
+    const server = app.listen(0, () => {
+      const port = server.address().port;
+      resolve({ server, port });
+    });
+  });
+}
+
+test('GET /api/health returns { ok: true }', async () => {
+  const app = createApp();
+  const { server, port } = await startServer(app);
+
+  try {
+    const result = await new Promise((resolve, reject) => {
+      http.get(`http://localhost:${port}/api/health`, (res) => {
+        let data = '';
+        res.on('data', (chunk) => { data += chunk; });
+        res.on('end', () => {
+          resolve({ status: res.statusCode, body: JSON.parse(data) });
+        });
+        res.on('error', reject);
+      });
+    });
+
+    assert.equal(result.status, 200);
+    assert.equal(result.body.ok, true);
+  } finally {
+    server.close();
+  }
+});