[yudelevi]

Part 2 of #45, stacked on #47.

Changelog entry for the free plan and a test that the UNAUTHENTICATED 401 object detail surfaces its message and keeps signup_url. No SDK code change.

Do not merge until discolike-platform !995 and !996 are on platform main: the free plan and the 401 object exist on neither platform development nor main yet (checked 2026-10-19). Docs: discolike-api-docs !50.

Confidence Score: 5/5

No code issues block merging once the author’s stated platform deployment gate is met.

Summary

Adds a free-plan changelog entry and a test for the no-credentials 401 response. No SDK code changes.

• SDK release notes and tests describe the free-plan signup response.

_{Reviews (1) · Last reviewed commit: "test(sdk): assert the 401 payload keeps ..." · Reviewed by Greptile}