fix(helpdesk): add border card around each agent widget for separation

Each agent section gets a border + border-radius wrapper. The inner
ticket table drops its own border to avoid double borders.

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

modules/helpdesk/web/js/helpdesk-team.js

@@ -75,7 +75,7 @@ if (container) {
    * Build a section widget for one agent — mirrors debitor dashboard section pattern.
    */
   function buildAgentWidget(m, isQueue) {
-    const section = h('section');
+    const section = h('section', 'helpdesk-team-widget');
 
     // Section title: "MM  Name   (count)" with line — same as helpdesk-support-section-title
     const title = h('h3', 'helpdesk-support-section-title');