feat(ui): stabilize shared M4.8 review viewer

apps/control-station/src/components/ObservationTimeline.tsx

@@ -101,13 +101,14 @@ export function ObservationTimeline({
           <Icon name="chevron-left" />
         </Button>
         <Button
+          className="observation-timeline__transport"
           size="compact"
-          variant="secondary"
+          variant="ghost"
           disabled={!buffered || !onPlayingChange}
+          aria-label={buffered ? (playing ? "Пауза" : "Воспроизвести") : "Только эфир"}
+          icon={<Icon name={playing ? "stop" : "play"} />}
           onClick={() => onPlayingChange?.(!playing)}
-        >
-          {buffered ? (playing ? "Пауза" : "Воспроизвести") : "Только эфир"}
-        </Button>
+        />
         {buffered && playbackRate !== undefined && onPlaybackRateChange ? (
           <Select
             label="Скорость воспроизведения"
@@ -117,7 +118,7 @@ export function ObservationTimeline({
               { value: "1", label: "1×" },
               { value: "2", label: "2×" },
             ]}
-            variant="split"
+            variant="inline"
             menuWidth="anchor"
             onChange={(value) => onPlaybackRateChange(Number(value))}
           />