fix: resolve all remaining linter issues (staticcheck, tagliatelle, lll)

- Fix staticcheck QF1011: Remove explicit type declaration for io.Writer variables
- Fix tagliatelle: Change all JSON tags from snake_case to camelCase
  - created_at → createdAt
  - keychain_item_name → keychainItemName
  - age_public_key → agePublicKey
  - age_priv_key_passphrase → agePrivKeyPassphrase
  - encrypted_longterm_key → encryptedLongtermKey
  - derivation_index → derivationIndex
  - public_key_hash → publicKeyHash
  - mnemonic_family_hash → mnemonicFamilyHash
  - gpg_key_id → gpgKeyId
- Fix lll: Break long function signature line to stay under 120 character limit

All linter issues have been resolved. The codebase now passes all linter checks.

internal/cli/crypto.go

@@ -124,7 +124,7 @@ func (cli *Instance) Encrypt(secretName, inputFile, outputFile string) error {
 	}
 
 	// Set up output writer
-	var output io.Writer = cli.cmd.OutOrStdout()
+	output := cli.cmd.OutOrStdout()
 	if outputFile != "" {
 		file, err := cli.fs.Create(outputFile)
 		if err != nil {
@@ -210,7 +210,7 @@ func (cli *Instance) Decrypt(secretName, inputFile, outputFile string) error {
 	}
 
 	// Set up output writer
-	var output io.Writer = cli.cmd.OutOrStdout()
+	output := cli.cmd.OutOrStdout()
 	if outputFile != "" {
 		file, err := cli.fs.Create(outputFile)
 		if err != nil {

internal/cli/unlockers.go

@@ -125,7 +125,7 @@ func (cli *Instance) UnlockersList(jsonOutput bool) error {
 	type UnlockerInfo struct {
 		ID        string    `json:"id"`
 		Type      string    `json:"type"`
-		CreatedAt time.Time `json:"created_at"`
+		CreatedAt time.Time `json:"createdAt"`
 		Flags     []string  `json:"flags,omitempty"`
 	}
 

internal/secret/keychainunlocker.go

@@ -28,7 +28,7 @@ var keychainItemNameRegex = regexp.MustCompile(`^[A-Za-z0-9._-]+$`)
 type KeychainUnlockerMetadata struct {
 	UnlockerMetadata
 	// Keychain item name
-	KeychainItemName string `json:"keychain_item_name"`
+	KeychainItemName string `json:"keychainItemName"`
 }
 
 // KeychainUnlocker represents a macOS Keychain-protected unlocker
@@ -40,9 +40,9 @@ type KeychainUnlocker struct {
 
 // KeychainData represents the data stored in the macOS keychain
 type KeychainData struct {
-	AgePublicKey         string `json:"age_public_key"`
-	AgePrivKeyPassphrase string `json:"age_priv_key_passphrase"`
-	EncryptedLongtermKey string `json:"encrypted_longterm_key"`
+	AgePublicKey         string `json:"agePublicKey"`
+	AgePrivKeyPassphrase string `json:"agePrivKeyPassphrase"`
+	EncryptedLongtermKey string `json:"encryptedLongtermKey"`
 }
 
 // GetIdentity implements Unlocker interface for Keychain-based unlockers

internal/secret/metadata.go

@@ -8,11 +8,11 @@ import (
 type VaultMetadata struct {
 	CreatedAt       time.Time `json:"createdAt"`
 	Description     string    `json:"description,omitempty"`
-	DerivationIndex uint32    `json:"derivation_index"`
+	DerivationIndex uint32    `json:"derivationIndex"`
 	// Double SHA256 hash of the actual long-term public key
-	PublicKeyHash string `json:"public_key_hash,omitempty"`
+	PublicKeyHash string `json:"publicKeyHash,omitempty"`
 	// Double SHA256 hash of index-0 key (for grouping vaults from same mnemonic)
-	MnemonicFamilyHash string `json:"mnemonic_family_hash,omitempty"`
+	MnemonicFamilyHash string `json:"mnemonicFamilyHash,omitempty"`
 }
 
 // UnlockerMetadata contains information about an unlocker

internal/secret/pgpunlocker.go

@@ -43,7 +43,7 @@ var (
 type PGPUnlockerMetadata struct {
 	UnlockerMetadata
 	// GPG key ID used for encryption
-	GPGKeyID string `json:"gpg_key_id"`
+	GPGKeyID string `json:"gpgKeyId"`
 }
 
 // PGPUnlocker represents a PGP-protected unlocker

internal/vault/management.go

@@ -197,7 +197,8 @@ func ListVaults(fs afero.Fs, stateDir string) ([]string, error) {
 }
 
 // processMnemonicForVault handles mnemonic processing for vault creation
-func processMnemonicForVault(fs afero.Fs, stateDir, vaultDir, vaultName string) (derivationIndex uint32, publicKeyHash string, familyHash string, err error) {
+func processMnemonicForVault(fs afero.Fs, stateDir, vaultDir, vaultName string) (
+	derivationIndex uint32, publicKeyHash string, familyHash string, err error) {
 	// Check if mnemonic is available in environment
 	mnemonic := os.Getenv(secret.EnvMnemonic)