fix(web3): normalize Ethereum addresses to lowercase to prevent case-sensitivity issues #2264

What kind of change does this PR introduce?

Bug fix - Resolves case-sensitivity issues with Ethereum addresses in SIWE (Sign-In with Ethereum) implementation.

What is the current behavior?

Ethereum addresses are stored with their original case (EIP-55 checksum format uses mixed case). This causes lookup failures when users sign in with a different case representation of the same address, as provider_id matching is case-sensitive.

What is the new behavior?

Ethereum addresses are now normalized to lowercase at parse time in parser.go. This ensures consistent storage and lookup regardless of the case used during sign-in.

Changes:

• internal/utilities/siwe/parser.go - Normalize address to lowercase
• internal/utilities/siwe/parser_test.go - Update test expectations

Migration Notes

This fix applies to new signups only. Existing users with checksummed Ethereum addresses in provider_id may need manual migration.

For existing deployments with web3 users:

-- Check affected rows first
SELECT COUNT(*) FROM auth.identities 
WHERE provider = 'web3' 
 AND provider_id LIKE 'web3:ethereum:0x%'
 AND provider_id != LOWER(provider_id);
-- Normalize addresses to lowercase
UPDATE auth.identities
SET provider_id = LOWER(provider_id)
WHERE provider = 'web3'
 AND provider_id LIKE 'web3:ethereum:0x%';

Note: For large tables, consider running in batches to avoid long locks.

Additional context

• Ethereum addresses are case-insensitive by design (EIP-55 uses mixed case only for checksum verification)
• The bulk migration was intentionally omitted per reviewer feedback to avoid performance issues on large auth.identities tables