Bittensor ships Null Consensus: 2,500 slots per subnet and fee-free PoW registration

• —Null mode lets only the largest-stake validator set weights, skipping Yuma consensus and bonds
• —Slot cap rises from 256 to 2,500, shared across a subnet's emission mechanisms
• —Switching back to Yuma requires pruning the subnet to 256 identifiers first
• —pow_register lets miners earn a slot via proof-of-work with no TAO burn or tx fee