Switch Emojis to Tabler icons.

templates/invitations/send.html

@@ -14,7 +14,7 @@
             </div>
             <div class="header-actions">
                 <a href="{{ url_for('invitations.list_invitations') }}" class="btn btn-secondary">
-                    <span class="icon">←</span>
+                    <i class="ti ti-arrow-left"></i>
                     Back to Invitations
                 </a>
             </div>
@@ -26,7 +26,7 @@
         <div class="card invitation-form-card">
             <div class="card-header">
                 <h2 class="card-title">
-                    <span class="icon">👥</span>
+                    <span class="icon"><i class="ti ti-users"></i></span>
                     Invitation Details
                 </h2>
             </div>