feat(helpdesk): separate queue from agents in team dashboard with wait time

Queue detection: any member with 'warteschlange' in support_user name
(or empty) is treated as queue, not as a regular agent.

Current tab: queue cards shown at top with a wait time summary
(Ø/Min/Max from open ticket ages). Agents listed below.

Historical tab: queue cards shown before agents, same performance
widget pattern.

No backend changes — purely client-side separation using existing data.

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

modules/helpdesk/web/css/helpdesk.css

@@ -220,6 +220,15 @@
     border-radius: 0;
   }
 
+  /* Team workload — queue wait time summary */
+  .helpdesk-team-queue-wait {
+    padding: calc(var(--app-spacing) * 0.5) calc(var(--app-spacing) * 0.75);
+    margin-bottom: calc(var(--app-spacing) * 0.5);
+    border: 1px dashed var(--app-muted-border-color);
+    border-radius: var(--app-radius, 0.375rem);
+    background: color-mix(in srgb, var(--app-muted-border-color) 10%, transparent);
+  }
+
   /* Team workload — inline avatar for section titles */
   .helpdesk-team-avatar-inline {
     display: inline-flex;