- Distance-class refactor: distances are a first-class axis instead of ~59 scattered literals.
- Four new race distances — 15K, 10 miles, 30K, 50K — with ten presets across levels. Existing plans stayed byte-identical through the refactor.
- Certification pass for every new-distance plan: km bands, plateau-aware long-run checks, back-to-back long days for the ultra.