feat(helpdesk): add team workload dashboard with per-agent metrics

New standalone page (helpdesk/team) showing support agent workload
aggregated from BC tickets. KPI bar (open, unassigned, avg age, resolved),
per-agent table sorted by open tickets, period selector (30/90/180/365d).
Global OData query via getTicketsForTeam() without customer filter.
New permission helpdesk.team-workload.view with admin role assignment.
Includes 6 PHPUnit tests for buildTeamWorkloadDashboard().

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

modules/helpdesk/templates/aside-helpdesk-panel.phtml

@@ -3,10 +3,12 @@
 $layoutNav = is_array($layoutNav ?? null) ? $layoutNav : [];
 $helpdeskNav = is_array($layoutNav['helpdesk.nav'] ?? null) ? $layoutNav['helpdesk.nav'] : [];
 $canManageSettings = !empty($helpdeskNav['can_manage_settings']);
+$canViewTeam = !empty($helpdeskNav['can_view_team']);
 
 $settingsActive = navActive('helpdesk/settings', true);
+$teamActive = navActive('helpdesk/team', true);
 $customersActive = navActive('helpdesk', true);
-if ($settingsActive['isActive']) {
+if ($settingsActive['isActive'] || $teamActive['isActive']) {
     $customersActive = ['class' => '', 'aria' => '', 'isActive' => false];
 }
 
@@ -17,6 +19,12 @@ $helpdeskNavItems = [
         'active' => $customersActive,
         'visible' => true,
     ],
+    [
+        'label' => t('Team'),
+        'path' => 'helpdesk/team',
+        'active' => $teamActive,
+        'visible' => $canViewTeam,
+    ],
     [
         'label' => t('Settings'),
         'path' => 'helpdesk/settings',