Rep-volume scaling for convergent movements (higher levels do more reps)

Movements that don't differ by load now scale reps with level: Rx ~1.2x base down
to Beg ~0.6x, rounded and forced monotonic. Applies to gymnastics, bodyweight, box
jumps, and wall ball; barbell/KB (load-differentiated) and monostructural distance
(shared buy-in) are left unchanged. So Rx/Adv+/Adv are now distinct on engine-style
workouts (e.g. OP-0070 wall ball 14/13/12, toes-to-bar 12/11/10) instead of identical.

Author: OneMuppet