Heavy Duty I prescriptive training system encoding Mentzer's methodology.

- 4-day split program (Chest & Back, Legs, Shoulders, Arms)
- Prescription engine with pre-exhaust superset structure
- Strict progression logic (+5kg large / +2.5kg small muscles)
- Recovery gating with stall-based extension and override
- Onboarding via experience level (Novice/Intermediate/Advanced)
- Session logging with full progression analysis
- Exercise substitution (33 alternatives for 17 canonical movements)
- Objectivist aesthetic: black/gold, serif, rectilinear

Stack: Hunchentoot, Mito/SQLite, Djula, SBCL