Third tier of the ingestion API (spec Section 4). Powers one-off
events with irregular shapes where neither record_winner (too
simple) nor typed add_events (too verbose) fits cleanly.
EventBuilder accumulates teams, weights, and outcome. Supports:
- .team([keys]) — add a team
- .weights([w..]) — per-member weights on the most-recently-added team
- .ranking([ranks]) — explicit per-team ranks
- .winner(i) — convenience: team i wins, others tied
- .draw() — all teams tied
- .commit() — finalize into an Event<T, K> and delegate to add_events
Part of T2 of docs/superpowers/specs/2026-04-23-trueskill-engine-redesign-design.md.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>