[log] Add debug logging to guard registry

[github-actions]

Summary

Enhanced internal/guard/registry.go with debug logging for better troubleshooting and development visibility.

Changes Made

• Added debug logger with namespace guard:registry following project conventions
• Added logging to key functions:
  • NewRegistry() - Logs registry creation
  • Register() - Logs guard registration with server ID and guard name
  • Get() - Logs guard retrieval attempts and results
  • Remove() - Logs guard removal operations
  • CreateGuard() - Logs guard factory operations with type resolution

Debug Logging Features

All debug logs:

• Write to stderr with colors and time diffs when DEBUG=guard:* or DEBUG=*
• Write to file logger (text-only) for persistent troubleshooting
• Use meaningful parameter values (serverID, guardName) without side effects
• Follow the pkg:filename naming convention

Testing

Enable debug logging with:

DEBUG=guard:* ./awmg --config config.toml

Compliance

✅ Single file modified (focused PR)
✅ No test files modified
✅ Logger naming follows pkg:filename convention
✅ No side effects in log arguments
✅ Meaningful log messages for debugging
✅ No duplicate logging with existing logs
✅ Proper import formatting

AI generated by Go Logger Enhancement