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/vault/secrets.go

@@ -89,6 +89,7 @@ func isValidSecretName(name string) bool {
 
 	// Check the basic pattern
 	matched, _ := regexp.MatchString(`^[a-z0-9\.\-\_\/]+$`, name)
+
 	return matched
 }
 
@@ -221,7 +222,10 @@ func (v *Vault) AddSecret(name string, value []byte, force bool) error {
 		return fmt.Errorf("failed to set current version: %w", err)
 	}
 
-	secret.Debug("Successfully added secret version to vault", "secret_name", name, "version", versionName, "vault_name", v.Name)
+	secret.Debug("Successfully added secret version to vault",
+		"secret_name", name, "version", versionName,
+		"vault_name", v.Name)
+
 	return nil
 }