fix(ui): ensure proper alignment of output stream video (yondonfu#71)

This commit ensures that the output video stream element takes the full height
of its parent div, improving layout consistency and visual alignment.

ui/src/components/room.tsx

@@ -70,7 +70,7 @@ function MediaStreamPlayer({ stream }: MediaStreamPlayerProps) {
         ref={videoRef}
         autoPlay
         playsInline
-        className="w-full h-full"
+        className="w-full h-full object-cover"
       />
       {needsPlayButton && (
         <div className="absolute inset-0 flex items-center justify-center bg-black/50">