feat(api): standardize errors as problem details

apps/web/src/app/api/[...path]/route.test.ts

@@ -0,0 +1,18 @@
+import { describe, expect, it } from "vitest";
+import { GET } from "./route";
+
+describe("unknown API routes", () => {
+  it("return an RFC 9457 not-found problem", async () => {
+    const response = GET(new Request("http://localhost/api/does-not-exist"));
+
+    expect(response.status).toBe(404);
+    expect(response.headers.get("content-type")).toBe("application/problem+json");
+    expect(await response.json()).toEqual({
+      type: "urn:error:not-found",
+      title: "API route not found",
+      status: 404,
+      detail: "The requested API route does not exist.",
+      instance: "/api/does-not-exist",
+    });
+  });
+});

apps/web/src/app/api/[...path]/route.ts

@@ -0,0 +1,20 @@
+import { problemDetails } from "@minecraft-account-manager/contracts";
+import { problemInstance, problemResponse } from "@/lib/problem-response";
+
+function notFound(request: Request) {
+  const instance = problemInstance(request);
+  return problemResponse(problemDetails(
+    "urn:error:not-found",
+    "API route not found",
+    404,
+    "The requested API route does not exist.",
+    instance,
+  ));
+}
+
+export const GET = notFound;
+export const POST = notFound;
+export const PUT = notFound;
+export const PATCH = notFound;
+export const DELETE = notFound;
+export const OPTIONS = notFound;