fix: resolve all revive linter issues

Added missing package comments:
- cmd/secret/main.go
- internal/cli/cli.go
- internal/secret/constants.go
- internal/vault/management.go
- pkg/bip85/bip85.go

Fixed comment format issues for exported items:
- EnvStateDir, EnvMnemonic, EnvUnlockPassphrase, EnvGPGKeyID in constants.go
- Metadata, UnlockerMetadata, SecretMetadata, Configuration in metadata.go
- AppBIP39, AppHDWIF, AppXPRV in bip85.go

Replaced unused parameters with underscore (_):
- generate.go:39 - parameter 'args'
- init.go:30 - parameter 'args'
- unlockers.go:39,77,102 - parameter 'args' or 'cmd'
- vault.go:37 - parameter 'args'
- management.go:34 - parameter 'target'

internal/vault/metadata.go

@@ -12,13 +12,17 @@ import (
 	"github.com/spf13/afero"
 )
 
-// Alias the metadata types from secret package for convenience
-type (
-	Metadata         = secret.VaultMetadata
-	UnlockerMetadata = secret.UnlockerMetadata
-	SecretMetadata   = secret.Metadata
-	Configuration    = secret.Configuration
-)
+// Metadata is an alias for secret.VaultMetadata
+type Metadata = secret.VaultMetadata
+
+// UnlockerMetadata is an alias for secret.UnlockerMetadata
+type UnlockerMetadata = secret.UnlockerMetadata
+
+// SecretMetadata is an alias for secret.Metadata
+type SecretMetadata = secret.Metadata
+
+// Configuration is an alias for secret.Configuration
+type Configuration = secret.Configuration
 
 // ComputeDoubleSHA256 computes the double SHA256 hash of data and returns it as hex
 func ComputeDoubleSHA256(data []byte) string {