fix: remove unused isPlaying state variable in VideoPlayer

- Remove unused isPlaying state that was causing TypeScript error TS6133
- Component only needs showPlayButton to control play button overlay visibility
- Fixes build error: 'isPlaying' is declared but its value is never read

admin-frontend/src/pages/VideoPlayer.tsx

@@ -6,7 +6,6 @@ export default function VideoPlayer() {
   const { id } = useParams<{ id: string }>()
   const videoId = id ? parseInt(id, 10) : null
   const videoRef = useRef<HTMLVideoElement>(null)
-  const [isPlaying, setIsPlaying] = useState(false)
   const [showPlayButton, setShowPlayButton] = useState(true)
 
   const videoUrl = videoId ? videosApi.getVideoUrl(videoId) : ''
@@ -14,13 +13,11 @@ export default function VideoPlayer() {
   const handlePlay = () => {
     if (videoRef.current) {
       videoRef.current.play()
-      setIsPlaying(true)
       setShowPlayButton(false)
     }
   }
 
   const handlePause = () => {
-    setIsPlaying(false)
     setShowPlayButton(true)
   }
 
@@ -34,17 +31,14 @@ export default function VideoPlayer() {
     if (!video) return
 
     const handlePlayEvent = () => {
-      setIsPlaying(true)
       setShowPlayButton(false)
     }
 
     const handlePauseEvent = () => {
-      setIsPlaying(false)
       setShowPlayButton(true)
     }
 
     const handleEnded = () => {
-      setIsPlaying(false)
       setShowPlayButton(true)
     }