fix: resolve all nlreturn linter errors

Add blank lines before return statements in all files to satisfy
the nlreturn linter. This improves code readability by providing
visual separation before return statements.

Changes made across 24 files:
- internal/cli/*.go
- internal/secret/*.go
- internal/vault/*.go
- pkg/agehd/agehd.go
- pkg/bip85/bip85.go

All 143 nlreturn issues have been resolved.

internal/cli/init.go

@@ -29,6 +29,7 @@ func NewInitCmd() *cobra.Command {
 // RunInit is the exported function that handles the init command
 func RunInit(cmd *cobra.Command, args []string) error {
 	cli := NewCLIInstance()
+
 	return cli.Init(cmd)
 }
 
@@ -42,6 +43,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 
 	if err := cli.fs.MkdirAll(stateDir, secret.DirPerms); err != nil {
 		secret.Debug("Failed to create state directory", "error", err)
+
 		return fmt.Errorf("failed to create state directory: %w", err)
 	}
 
@@ -62,12 +64,14 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 		mnemonicStr, err = readLineFromStdin("Enter your BIP39 mnemonic phrase: ")
 		if err != nil {
 			secret.Debug("Failed to read mnemonic from stdin", "error", err)
+
 			return fmt.Errorf("failed to read mnemonic: %w", err)
 		}
 	}
 
 	if mnemonicStr == "" {
 		secret.Debug("Empty mnemonic provided")
+
 		return fmt.Errorf("mnemonic cannot be empty")
 	}
 
@@ -75,6 +79,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 	secret.DebugWith("Validating BIP39 mnemonic", slog.Int("word_count", len(strings.Fields(mnemonicStr))))
 	if !bip39.IsMnemonicValid(mnemonicStr) {
 		secret.Debug("Invalid BIP39 mnemonic provided")
+
 		return fmt.Errorf("invalid BIP39 mnemonic phrase\nRun 'secret generate mnemonic' to create a valid mnemonic")
 	}
 
@@ -94,6 +99,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 	vlt, err := vault.CreateVault(cli.fs, cli.stateDir, "default")
 	if err != nil {
 		secret.Debug("Failed to create default vault", "error", err)
+
 		return fmt.Errorf("failed to create default vault: %w", err)
 	}
 
@@ -102,6 +108,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 	metadata, err := vault.LoadVaultMetadata(cli.fs, vaultDir)
 	if err != nil {
 		secret.Debug("Failed to load vault metadata", "error", err)
+
 		return fmt.Errorf("failed to load vault metadata: %w", err)
 	}
 
@@ -109,6 +116,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 	ltIdentity, err := agehd.DeriveIdentity(mnemonicStr, metadata.DerivationIndex)
 	if err != nil {
 		secret.Debug("Failed to derive long-term key", "error", err)
+
 		return fmt.Errorf("failed to derive long-term key from mnemonic: %w", err)
 	}
 	ltPubKey := ltIdentity.Recipient().String()
@@ -127,6 +135,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 		passphraseStr, err = readSecurePassphrase("Enter passphrase for unlocker: ")
 		if err != nil {
 			secret.Debug("Failed to read unlock passphrase", "error", err)
+
 			return fmt.Errorf("failed to read passphrase: %w", err)
 		}
 	}
@@ -136,6 +145,7 @@ func (cli *Instance) Init(cmd *cobra.Command) error {
 	passphraseUnlocker, err := vlt.CreatePassphraseUnlocker(passphraseStr)
 	if err != nil {
 		secret.Debug("Failed to create unlocker", "error", err)
+
 		return fmt.Errorf("failed to create unlocker: %w", err)
 	}