fix: resolve type errors across test suite

tests/unit/teapot.test.ts

@@ -0,0 +1,25 @@
+import { describe, test, expect } from "bun:test";
+import teapot from "../../src/api/teapot";
+
+describe("Teapot route handler", () => {
+  test("GET / returns 418 status", async () => {
+    const res = await teapot.request("/");
+    expect(res.status).toBe(418);
+  });
+
+  test("response body has correct shape", async () => {
+    const res = await teapot.request("/");
+    const body = await res.json();
+    expect(body).toEqual({
+      status: 418,
+      message: "I'm not a teapot",
+      successful: true,
+    });
+  });
+
+  test("returns JSON content type", async () => {
+    const res = await teapot.request("/");
+    const ct = res.headers.get("content-type");
+    expect(ct).toContain("application/json");
+  });
+});