fix(helpdesk): remove overflow:hidden from team widget to fix tooltip clipping

Move border-radius to the section title header directly instead of
relying on overflow:hidden on the parent. Tooltips on trend arrows
are no longer clipped by the card boundary.

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

modules/helpdesk/web/css/helpdesk.css

@@ -192,7 +192,6 @@
     border: 1px solid var(--app-muted-border-color);
     border-radius: var(--app-radius, 0.375rem);
     margin-bottom: calc(var(--app-spacing) * 0.5);
-    overflow: hidden;
   }
 
   .helpdesk-team-widget > .helpdesk-support-section-title {
@@ -200,6 +199,7 @@
     padding: calc(var(--app-spacing) * 0.5) calc(var(--app-spacing) * 0.75);
     background: color-mix(in srgb, var(--app-muted-border-color) 15%, transparent);
     border-bottom: 1px solid var(--app-muted-border-color);
+    border-radius: var(--app-radius, 0.375rem) var(--app-radius, 0.375rem) 0 0;
   }
 
   .helpdesk-team-widget > .helpdesk-support-section-title::after {