EIP-8358 Net Gas Metering for Account Changes

EIP-8358 introduces net gas metering for account changes, mirroring EIP-2200's storage scheme. Accounts count as changed when balance or nonce differs from transaction start. CALL_VALUE replaced by CALL_VALUE_BASE_GAS, with CLEAN_BALANCE_CHANGE_GAS for unmodified accounts. Transfers between unmodified accounts cost 8000 gas; already-modified accounts cost 4000. BALANCE_RESET_REFUND applies when balance returns to original.