Plan covers 8 TDD tasks landing the /healthz endpoint and structured
JSON logs behind the platform contract (#25).
Also: spec updated to use JSON (not YAML) as the log-config source —
avoids a pyyaml runtime dep and removes drift between the dict tests
apply and the file uvicorn reads.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>