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/generate.go

@@ -38,6 +38,7 @@ func newGenerateMnemonicCmd() *cobra.Command {
 			`or 'secret import'.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			cli := NewCLIInstance()
+
 			return cli.GenerateMnemonic(cmd)
 		},
 	}
@@ -147,12 +148,14 @@ func (cli *Instance) GenerateSecret(
 // generateRandomBase58 generates a random base58 string of the specified length
 func generateRandomBase58(length int) (string, error) {
 	const base58Chars = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+
 	return generateRandomString(length, base58Chars)
 }
 
 // generateRandomAlnum generates a random alphanumeric string of the specified length
 func generateRandomAlnum(length int) (string, error) {
 	const alnumChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
 	return generateRandomString(length, alnumChars)
 }