fix(ui): показывать неизвестные поля сертификатов явно

components/data-grids/certificate-days-cell.tsx

@@ -0,0 +1,28 @@
+"use client"
+
+import type { CertificateView } from "@/lib/certificate-view"
+import { cn } from "@/lib/utils"
+
+function daysLeftColor(days: number | null): string {
+  if (days === null) return "text-muted-foreground"
+  if (days <= 7) return "text-destructive"
+  if (days <= 30) return "text-warning"
+  return "text-success"
+}
+
+export function CertDaysCell({ cert }: { cert: CertificateView }) {
+  return (
+    <div className="flex flex-wrap items-center justify-between gap-1 text-xs">
+      <span className={cn("font-mono font-medium", daysLeftColor(cert.daysLeft))}>
+        {cert.daysLeft === null
+          ? "Срок неизвестен"
+          : cert.daysLeft < 0
+            ? "Истёк " + -cert.daysLeft + "д назад"
+            : cert.daysLeft + "д осталось"}
+      </span>
+      <span className="text-muted-foreground text-[10px] break-all">
+        {cert.validUntil ?? "Дата окончания неизвестна"}
+      </span>
+    </div>
+  )
+}