Output addresses in EIP-55 checksum format

[heswithme]

Output addresses in EIP-55 checksum format

Summary

This PR adds EIP-55 checksum formatting to all output addresses, improving compatibility with Ethereum tooling and making addresses more recognizable.

Changes

• Added src/checksum.rs module implementing EIP-55 checksum address formatting
• Modified address output in src/lib.rs to use checksum format instead of lowercase hex

Details

The implementation follows the EIP-55 specification:

1. Hash the lowercase hex address (without 0x prefix) using Keccak256
2. For each character in the address that is a letter (a-f), uppercase it if the corresponding bit in the hash is 1

Example Output

Before:

0xe6ab51a5f6e3ff03ab49e6000000000000000000000000000000000000000000 => 0x003833d688046bc9b40aaf4629589850beb7d70e

After:

0xe6ab51a5f6e3ff03ab49e6000000000000000000000000000000000000000000 => 0x003833d688046bc9b40aAF4629589850bEb7d70e

Testing

• Added unit tests for checksum implementation with official EIP-55 test vectors
• Manually tested mining functionality to ensure output is correctly formatted
• No changes to core mining logic or performance

Backward Compatibility

This change only affects the display format of addresses in output. It does not affect:

• Pattern matching logic
• Mining performance
• Input parsing
• File format compatibility