EVM Wei Unit Converter

This tool converts an EVM value between wei, gwei, and eth, taking a numeric value string and its unit and returning all three units as strings to avoid precision loss. Inputs are: value (string) as the base-10 numeric amount in the specified unit, and unit (string enum: wei, gwei, eth) indicating the source unit. It performs deterministic scaling between units suitable for financial agents and transaction planning. The output must strictly validate against the system-provided structured output schema for this tool, with only the allowed fields, correct string types for amounts, and values derived solely from the given inputs.