fix(evm): decode web3_sha3 DATA before hashing

[vetclippy]

Abstract

• Closes #<ISSUE_NUMBER>

web3_sha3 was accepting its input as a Go string. As a result, hexutil.Bytes(input) converted the hexadecimal string into its ASCII bytes instead of decoding the Ethereum DATA value.

Summary of Changes

• Change APIWeb3.Sha3 to accept hexutil.Bytes.
• Let the JSON-RPC layer decode the 0x-prefixed input.
• Add direct unit coverage for the Keccak-256 result.
• Add HTTP JSON-RPC coverage for web3_sha3.

Testing Approach

• go test ./evm/jsonrpc -count=1
• git diff --check

Why this Solution Works

hexutil.Bytes implements Ethereum-compatible hexadecimal JSON decoding. The method now hashes the decoded bytes, matching the behavior of Geth and the Ethereum JSON-RPC specification.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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