secret version list no longer shows a version without NOT_AFTER as expired (closes #150)

STATUS was `expired` for every version other than the current one, so after
a promote the newest version, which has no NOT_AFTER, read `expired`. STATUS
is now `current` for the current version, `expired` for another version
whose NOT_AFTER has passed, and `inactive` for any other version. README
describes the three.

Judgement call: the issue left the third word to the owner; `inactive` is
the word the plan comment on the issue chose.

Model: opus-5-5

internal/cli/version.go

@@ -229,9 +229,13 @@ func printVersionRow(
 	}
 
 	// Determine status
-	status := "expired"
-	if version == currentVersion {
+	status := "inactive"
+
+	switch {
+	case version == currentVersion:
 		status = "current"
+	case sv.Metadata.NotAfter != nil && sv.Metadata.NotAfter.Before(time.Now()):
+		status = "expired"
 	}
 
 	// Format timestamps