feat: add session updates and message dialogs

frontend/src/components/pages/ComponentsToolsPage.tsx

@@ -980,7 +980,7 @@ function ClientToolFields({
       )}
       <p className="text-xs leading-5 text-muted-foreground">
         函数名必须与客户端注册的 handler 名称一致，例如
-        set_photo_button_visible。
+        set_photo_button_visible 或 show_message。
       </p>
     </div>
   );

frontend/src/components/pages/MobileCallPage.tsx

@@ -30,6 +30,7 @@ import {
   SelectTrigger,
   SelectValue,
 } from "@/components/ui/select";
+import { ClientMessageDialog } from "@/components/client-message-dialog";
 import { useCameraPreview } from "@/hooks/use-camera-preview";
 import { usePhotoCaptureTool } from "@/hooks/use-photo-capture-tool";
 import {
@@ -483,6 +484,7 @@ export function MobileCallPage({ assistantId }: { assistantId: string }) {
   return (
     <main className="flex h-dvh w-full items-center justify-center overflow-hidden bg-black lg:p-4">
       <audio ref={audioRef} autoPlay playsInline className="hidden" />
+      <ClientMessageDialog preview={preview} />
       <div
         data-testid="mobile-call-viewport"
         className="relative isolate h-dvh min-h-80 w-full overflow-hidden bg-[#07101a] text-white lg:h-[calc(100dvh-2rem)] lg:min-h-0 lg:w-auto lg:aspect-[9/16] lg:rounded-[2rem] lg:ring-1 lg:ring-white/15 lg:shadow-2xl"