The struct holds prior/beta/drift — a rating configuration, not a person. The person-with-temporal-state is the Competitor (renamed in the next task). Resolves Player/Agent ambiguity. Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>