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'

pkg/bip85/bip85.go

@@ -1,3 +1,4 @@
+// Package bip85 implements BIP85 deterministic entropy derivation.
 package bip85
 
 import (
@@ -27,10 +28,12 @@ const (
 	// BIP85_KEY_HMAC_KEY is the HMAC key used for deriving the entropy
 	BIP85_KEY_HMAC_KEY = "bip-entropy-from-k" //nolint:revive // ALL_CAPS used for BIP85 constants
 
-	// Application numbers
-	AppBIP39  = 39     // BIP39 mnemonics
-	AppHDWIF  = 2      // WIF for Bitcoin Core
-	AppXPRV   = 32     // Extended private key
+	// AppBIP39 is the application number for BIP39 mnemonics
+	AppBIP39 = 39
+	// AppHDWIF is the application number for WIF (Wallet Import Format) for Bitcoin Core
+	AppHDWIF = 2
+	// AppXPRV is the application number for extended private key
+	AppXPRV = 32
 	APP_HEX   = 128169 //nolint:revive // ALL_CAPS used for BIP85 constants
 	APP_PWD64 = 707764 // Base64 passwords //nolint:revive // ALL_CAPS used for BIP85 constants
 	AppPWD85  = 707785 // Base85 passwords