revert(helpdesk): remove queue separation from team dashboard

Revert queue detection, wait time summary, and visual separation.
All members are treated equally again — queue appears as a normal
agent entry sorted by the existing criteria.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

modules/helpdesk/i18n/default_de.json

@@ -301,6 +301,5 @@
   "Current": "Aktuell",
   "Performance": "Leistung",
   "Historical": "Historisch",
-  "Queue": "Warteschlange",
-  "Wait time": "Wartezeit"
+  "Queue": "Warteschlange"
 }