EVM Contract Source and ABI Fetcher

This tool resolves verified Solidity source code, ABI, and related metadata for an EVM contract using a multi-strategy lookup (e.g., Sourcify first, then block explorer APIs). It accepts the following inputs: chain_id (integer network identifier), contract_address (0x-prefixed EVM contract address), and optional explorer_api_key for authenticated or rate-limited explorer access. Any additional JSON payload inputs supplied by upstream systems must be treated as authoritative when mapping fields. The tool must produce output that strictly validates against the system-provided structured output schema, with correct types, no extra keys, and all optional fields omitted when the corresponding data is unavailable.