feat(outbound): add voice announcement on trunk congestion & clarify MoH options

public/index.php

@@ -3102,7 +3102,7 @@ $currentUser = Auth::getUsername();
                             <select id="ob-musicclass-select" name="moh_class" class="w-full px-3 py-2 rounded-lg bg-anthracite-900 border border-anthracite-700 text-xs text-white"></select>
                         </div>
                         <div>
-                            <label class="block text-xs font-medium text-slate-200 mb-1">Destination sur Congestion <span class="text-slate-400">(Échec total)</span></label>
+                            <label class="block text-xs font-medium text-slate-200 mb-1">📢 Si Trunks indisponibles <span class="text-slate-400">(Échec / Congestion)</span></label>
                             <select id="ob-congestion-dest-select" name="congestion_dest" class="w-full px-3 py-2 rounded-lg bg-anthracite-900 border border-anthracite-700 text-xs text-white"></select>
                         </div>
                     </div>