feat(dashboard): show every active employee in "Docházka dnes"

The attendance card listed only employees with a record today (present /
break / clocked-out / on-leave). Now every active employee appears;
those with no record today show as "absent" (Nepřítomen), so the card
reflects the whole team. Loads active users (was a bare count) and
appends the unrecorded ones.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/utils/dashboardHelpers.ts

@@ -16,6 +16,7 @@ export const STATUS_LABELS: Record<string, string> = {
   away: "Přestávka",
   out: "Nepřihlášen",
   leave: "Nepřítomen",
+  absent: "Nepřítomen",
 };
 
 // Re-exported from the single source of truth so the dashboard activity feed