Create a managed Python 3.11 sandbox. Two billing modes selected by 'timeout': ≤300s = flat rate (CPU $0.01, GPU varies)

Create a managed Python 3.11 sandbox. Two billing modes selected by 'timeout': ≤300s = flat rate (CPU $0.01, GPU varies). >300s = per-hour billing for the full requested lifetime, no refund on early terminate. Max 24h.