- Fixed gpgDecryptDefault to return *memguard.LockedBuffer instead of []byte
- Updated GPGDecryptFunc signature and all implementations
- Confirmed getSecretValue already returns LockedBuffer (was fixed earlier)
- Improved passphrase string handling by removing intermediate variables
- Note: String conversion for passphrases is unavoidable due to age library API
- All GPG decrypted data is now immediately protected in memory