Flaky/failing test: `should create a QR code with custom options` returns HTTP 400

[jaredwray]

Summary

The integration test test/link.test.ts > Link QR Code > should create a QR code with custom options fails deterministically against the live Hyphen API with Error: Fetch failed with status 400.

Root cause: a server-side API contract change, not the SDK or its dependencies.

Evidence

• The failing call is link.createQrCode(code, { title, backgroundColor, color, size: QrSize.MEDIUM }). The basic QR-create (empty body) returns 201; only the custom-options payload is rejected with 400. The SDK sends exactly the field names/values documented in the README.
• Not a transport/dependency issue. The stack runs through @cacheable/net. We upgraded @cacheable/net 2.0.7 → 2.0.8 (which switches from bundled undici to the runtime's native fetch) — CI still returns the identical 400. A local echo-server repro confirmed undici@7.24.7 and native globalThis.fetch send byte-for-byte identical requests for this payload (same body, content-length, headers).
• It regressed on the API side. This test and the createQrCode body were introduced together in PR chore: upgrading @cacheable/net to 2.0.1 #88, and main passed full CI — including this test — as recently as 2026-04-13. So the API previously accepted {"title","backgroundColor","color","size":"medium"} and now rejects it.

Current state (handled in PR #132)

• The live integration test is skipped (test.skip) with a TODO pointing here.
• A stubbed unit test (should build the request body when creating a QR code with options) was added so the custom-options request-body branches stay covered (100% coverage maintained).

To resolve

1. With valid HYPHEN_* credentials, call the QR-create endpoint with the custom-options body and capture the 400 response body to see what the API now expects.
2. Update src/link.ts createQrCode (and the README/types) to match the current contract — e.g. renamed/removed fields or a different color/size format.
3. Un-skip the integration test in test/link.test.ts (remove test.skip → test) and confirm green.

References

• PR root - chore: upgrade code quality dependencies + adopt pnpm 11 / Node 22-26 CI #132 (CI modernization; quarantine + coverage unit test)
• src/link.ts createQrCode (~line 487-523); body built ~line 499-505