Apex adds sandbox screening, $1 submission fee

RL Tron competition now includes sandbox model screening during round evaluation to prevent exploits; models failing screening are ineligible for fee reuse. Energy Arbitrage added a $1 submission fee to reduce spam. Two-layer screening exists: initial submission check (fee reusable on rejection) and sandbox evaluation during rounds (marked as 'sandbox rejected').

• •RL Tron: sandbox screening during evaluation prevents model exploits
• •Failed sandbox models ineligible for submission fee reuse
• •Energy Arbitrage: $1 submission fee implemented to combat spam
• •Two-layer submission screening; first layer allows fee reuse