Corbits_AgentPaymentBuyer

Version 2.1.0. Execute a Corbits x402-style paid HTTP call using the agent's EVM wallet: (1) read wallet native balances, (2) obtain payment requirements from an initial 402 response, (3) optionally render funding instructions from an inline template, (4) sign the payment requirements with WALLET_Sign using WALLET.evm, (5) retry the HTTP call with an X-PAYMENT header, and (6) record the successful paid call as an ARTIFACT_Update reference artifact with slug 'corbits_call_{txHash}'.