fix: resolve exported type stuttering issues (revive)

- Rename VaultMetadata to Metadata in internal/vault package to avoid stuttering
- Rename BIP85DRNG to DRNG in pkg/bip85 package to avoid stuttering
- Update all references in code and tests

internal/secret/secret_test.go

@@ -262,6 +262,7 @@ func isValidSecretName(name string) bool {
 			return false
 		}
 	}
+
 	return true
 }