Checkpoint: v4.0 media service, compose deploy, and verified docs

client/src/pages/LiveCamera.tsx

@@ -341,7 +341,7 @@ export default function LiveCamera() {
                   <div className="absolute inset-0 flex flex-col items-center justify-center text-white/60">
                     <CameraOff className="h-12 w-12 mb-3" />
                     <p className="text-sm">摄像头未启动</p>
-                    <Button variant="secondary" className="mt-3 gap-2" onClick={() => setShowSetupGuide(true)}>
+                    <Button data-testid="live-camera-start-button" variant="secondary" className="mt-3 gap-2" onClick={() => setShowSetupGuide(true)}>
                       <Camera className="h-4 w-4" />启动摄像头
                     </Button>
                   </div>
@@ -357,7 +357,7 @@ export default function LiveCamera() {
               {/* Controls bar */}
               <div className="flex items-center justify-center gap-3 p-3 bg-muted/30 flex-wrap">
                 {!cameraActive ? (
-                  <Button onClick={() => setShowSetupGuide(true)} className="gap-2">
+                  <Button data-testid="live-camera-toolbar-start-button" onClick={() => setShowSetupGuide(true)} className="gap-2">
                     <Camera className="h-4 w-4" />启动摄像头
                   </Button>
                 ) : (