Add health and ready endpoints

Author: lukekim

test/apps/vercel-nextjs/app/api/health/route.ts

@@ -0,0 +1,5 @@
+import { NextResponse } from 'next/server';
+
+export async function GET() {
+  return NextResponse.json({ status: 'ok' }, { status: 200 });
+}

test/apps/vercel-nextjs/app/api/ready/route.ts

@@ -0,0 +1,5 @@
+import { NextResponse } from 'next/server';
+
+export async function GET() {
+  return NextResponse.json({ status: 'ok' }, { status: 200 });
+}