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/integration_version_test.go

@@ -40,7 +40,9 @@ func TestVersionIntegrationWorkflow(t *testing.T) {
 	stateDir := "/test/state"
 
 	// Set mnemonic for testing
-	t.Setenv(secret.EnvMnemonic, "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about")
+	t.Setenv(secret.EnvMnemonic,
+		"abandon abandon abandon abandon abandon abandon "+
+			"abandon abandon abandon abandon abandon about")
 
 	// Create vault
 	vault, err := CreateVault(fs, stateDir, "test")
@@ -278,7 +280,7 @@ func TestVersionConcurrency(t *testing.T) {
 		done := make(chan bool, 10)
 		errors := make(chan error, 10)
 
-		for i := 0; i < 10; i++ {
+		for range 10 {
 			go func() {
 				value, err := vault.GetSecret(secretName)
 				if err != nil {
@@ -291,7 +293,7 @@ func TestVersionConcurrency(t *testing.T) {
 		}
 
 		// Wait for all goroutines
-		for i := 0; i < 10; i++ {
+		for range 10 {
 			<-done
 		}