Address case sensitivity handled inconsistently

Problem

Address comparison and normalization is inconsistent across the codebase. Some places use toLowerCase(), others don't, leading to potential mismatches.

Locations

• src/protocol/account.ts:231, 236, 268 - uses toLowerCase()
• Other comparison points may not normalize

Impact

• Address comparisons could fail unexpectedly
• Same address in different cases treated as different
• Potential security issues with allowlists/blocklists

Recommendation

1. Create a normalizeAddress() helper function
2. Use it consistently throughout the codebase
3. Consider using checksummed addresses (EIP-55) as canonical form

export function normalizeAddress(address: string): Address {
  // Validate and return checksummed address
  if (!isValidAddress(address)) {
    throw new InvalidAddressError(address);
  }
  return toChecksumAddress(address) as Address;
}

Priority

High - Correctness issue

Review src/protocol/account.ts at lines 231, 236, and 268, then search the codebase for other address comparison points. The work is done when address comparisons use a consistent normalization approach, including validation and checksummed canonicalization if adopted.