Implement buildApiClient(fetch, baseUrl)

Implement buildApiClient(fetch, baseUrl)

Write buildApiClient(fetch, baseUrl) that returns a small client object with .get(path) and .post(path, body) methods, both of which:

• Request baseUrl + path.
• post sends body JSON-encoded, with a Content-Type: application/json header.
• Throw an error mentioning the status code on any non-2xx response (same rule as fetchJson).
• Return the parsed JSON body on success.

const client = buildApiClient(fetch, "https://api.example.com");
await client.get("/users/1");
await client.post("/users", { name: "Ada" });