v0.5.0 (Ni3D): - Real-time 360° 3D Athlete Engine with 3D floor mat, depth sorting, and 1:1 rep synchronization - Bilingual Voice Coach (DE/EN) with spoken exercise explanations and live rep counting (1..10) - Instant explanation mute button (DOWN) and configurable rep tempo (3s / 4s / 5s) - Always-on backlight during workouts