fix: resolve errcheck, gosec, and mnd linter errors

- Fixed unhandled errors in init.go (os.Setenv/Unsetenv)
- Fixed unhandled errors in test_helpers.go (os.Setenv/Unsetenv)
- Replaced magic numbers with named constants:
  - defaultSecretLength = 16
  - mnemonicEntropyBits = 128
  - tabWriterPadding = 2

internal/cli/version.go

@@ -12,6 +12,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
+const (
+	tabWriterPadding = 2
+)
+
 // newVersionCmd returns the version management command
 func newVersionCmd() *cobra.Command {
 	cli := NewCLIInstance()
@@ -110,8 +114,8 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 	}
 
 	// Create table writer
-	w := tabwriter.NewWriter(cmd.OutOrStdout(), 0, 0, 2, ' ', 0)
-	fmt.Fprintln(w, "VERSION\tCREATED\tSTATUS\tNOT_BEFORE\tNOT_AFTER")
+	w := tabwriter.NewWriter(cmd.OutOrStdout(), 0, 0, tabWriterPadding, ' ', 0)
+	_, _ = fmt.Fprintln(w, "VERSION\tCREATED\tSTATUS\tNOT_BEFORE\tNOT_AFTER")
 
 	// Load and display each version's metadata
 	for _, version := range versions {
@@ -125,7 +129,7 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 			if version == currentVersion {
 				status = "current (error)"
 			}
-			fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", version, "-", status, "-", "-")
+			_, _ = fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", version, "-", status, "-", "-")
 
 			continue
 		}
@@ -152,10 +156,10 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 			notAfter = sv.Metadata.NotAfter.Format("2006-01-02 15:04:05")
 		}
 
-		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", version, createdAt, status, notBefore, notAfter)
+		_, _ = fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", version, createdAt, status, notBefore, notAfter)
 	}
 
-	w.Flush()
+	_ = w.Flush()
 
 	return nil
 }