Fix "undefined joined your line" in Overview recent-activity

The referral row read r.email but dashboard referral objects carry r.name
(username or masked email). Use r.name with an escape + fallback.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/assets/my.js

@@ -262,7 +262,7 @@
         for (const r of (d.referrals || []).slice(0, 3)) {
           const div = document.createElement('div');
           div.className = 'row';
-          div.innerHTML = '<span>🤝 ' + r.email + ' joined your line</span><span class="tx muted small">'
+          div.innerHTML = '<span>🤝 ' + esc(r.name || r.email || 'A new member') + ' joined your line</span><span class="tx muted small">'
             + new Date(r.joined).toLocaleDateString() + '</span>';
           rows.push(div);
         }