TDD, green suite at every boundary. Task 4 is deliberately one cross-cutting
commit: the origin's key and the log's player field are read on both sides of
the HTTP boundary, so renaming them in separate tasks would leave a suite red
at the seam.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QYa9u7Kdxv5gX4AnwWexy8
