Challenge 2: Mount at a Custom Path With a Health Check — Possible Solution
====================================================================

import express from "express";
import { expressMiddleware } from "@apollo/server/express4";

const app = express();
const server = new ApolloServer({ typeDefs, resolvers });
await server.start();

// Plain ordinary REST route, defined just like in the Express courses —
// nothing GraphQL-specific about this at all.
app.get("/health", (req, res) => {
  res.json({ status: "ok" });
});

// GraphQL mounted at a custom path instead of the default "/graphql".
app.use(
  "/api/graphql",
  express.json(),
  expressMiddleware(server, {
    async context({ req }) {
      return { userLoader: createUserLoader(pool) };
    },
  })
);

app.listen(4000);

WHY THIS WORKS
--------------
- app.use("/api/graphql", ...) is the ONLY change needed to relocate the
  GraphQL endpoint — the mount path passed to app.use() is just an
  ordinary Express routing decision, completely independent of anything
  inside the schema, resolvers, or context function. GraphQL doesn't
  care what URL path it's served from; the client just needs to be
  configured to send its queries to whatever path the server actually
  mounts it at.
- app.get("/health", ...) is defined as a COMPLETELY separate, ordinary
  Express route, using the exact same app.get() pattern from the
  Express courses — this demonstrates directly that a GraphQL server
  doesn't have to be the ONLY thing an Express app serves. A single app
  can freely mix a GraphQL endpoint with conventional REST routes for
  things that don't need (or don't benefit from) GraphQL's query
  flexibility, like a simple health check a load balancer or monitoring
  tool might poll.
- This is a very common real-world pattern: GraphQL for the application's
  actual data-fetching needs, plain REST for auxiliary concerns like
  health checks, webhooks, or file uploads — echoing Chapter 1's honest
  "REST still wins for certain things" framing, now shown living
  side-by-side with GraphQL in the same running server rather than as an
  either/or choice for the whole application.