feat: redesign VideoPreview with dark broadcast monitor frame

frontend/src/components/VideoPreview.tsx

@@ -1,4 +1,4 @@
-import React, { useEffect, useRef } from 'react';
+import React, { useEffect, useRef, useState } from 'react';
 import Hls from 'hls.js';
 
 interface VideoPreviewProps {
@@ -8,60 +8,82 @@ interface VideoPreviewProps {
 export function VideoPreview({ portIndex }: VideoPreviewProps) {
   const videoRef = useRef<HTMLVideoElement>(null);
   const hlsRef = useRef<Hls | null>(null);
+  const [hasSignal, setHasSignal] = useState(false);
 
   useEffect(() => {
     const src = `/hls/port_${portIndex}.m3u8`;
+    setHasSignal(false);
 
-    if (!videoRef.current) {
+    if (!videoRef.current) return;
-      return;
-    }
 
     if (Hls.isSupported()) {
-      const hls = new Hls({
+      const hls = new Hls({ enableWorker: true, lowLatencyMode: true });
-        enableWorker: true,
-        lowLatencyMode: true,
-      });
-
       hlsRef.current = hls;
       hls.loadSource(src);
       hls.attachMedia(videoRef.current);
-
       hls.on(Hls.Events.MANIFEST_PARSED, () => {
-        videoRef.current?.play().catch((err) => {
+        setHasSignal(true);
-          console.error('Failed to autoplay video:', err);
+        videoRef.current?.play().catch(console.error);
-        });
       });
-
+      hls.on(Hls.Events.ERROR, (_event, data) => {
-      hls.on(Hls.Events.ERROR, (event, data) => {
+        if (data.fatal) setHasSignal(false);
-        console.error('HLS.js error:', data);
       });
     } else if (videoRef.current.canPlayType('application/vnd.apple.mpegurl')) {
-      // Safari native HLS support
       videoRef.current.src = src;
-      videoRef.current.play().catch((err) => {
+      videoRef.current.addEventListener('canplay', () => setHasSignal(true), { once: true });
-        console.error('Failed to autoplay video:', err);
+      videoRef.current.play().catch(console.error);
-      });
-    } else {
-      console.error('HLS streaming is not supported in this browser');
     }
 
     return () => {
-      if (hlsRef.current) {
+      hlsRef.current?.destroy();
-        hlsRef.current.destroy();
+      hlsRef.current = null;
-        hlsRef.current = null;
-      }
     };
   }, [portIndex]);
 
   return (
-    <div className="bg-black rounded-lg overflow-hidden aspect-video">
+    <div style={{ background: '#000', borderRadius: 2, overflow: 'hidden', position: 'relative', aspectRatio: '16/9' }}>
       <video
         ref={videoRef}
-        className="w-full h-full"
+        style={{ width: '100%', height: '100%', objectFit: 'cover', display: hasSignal ? 'block' : 'none' }}
         controls
         muted
         playsInline
       />
+
+      {!hasSignal && (
+        <div style={{
+          position: 'absolute', inset: 0,
+          display: 'flex', flexDirection: 'column', alignItems: 'center', justifyContent: 'center',
+          background: 'linear-gradient(135deg, #090d15 0%, #0e1525 100%)',
+        }}>
+          {/* Grid pattern */}
+          <div style={{
+            position: 'absolute', inset: 0,
+            backgroundImage: 'linear-gradient(rgba(26,58,255,0.04) 1px, transparent 1px), linear-gradient(90deg, rgba(26,58,255,0.04) 1px, transparent 1px)',
+            backgroundSize: '32px 32px',
+          }} />
+          <span style={{ fontSize: 40, color: 'var(--text-muted)', zIndex: 1, marginBottom: 10 }}>▶</span>
+          <span style={{
+            fontFamily: 'var(--font-mono)', fontSize: 11, color: 'var(--text-muted)',
+            letterSpacing: '0.15em', textTransform: 'uppercase', zIndex: 1,
+          }}>
+            Port {portIndex} — No HLS Feed
+          </span>
+        </div>
+      )}
+
+      {/* HLS badge */}
+      <div style={{
+        position: 'absolute', top: 10, right: 10,
+        fontFamily: 'var(--font-mono)', fontSize: 9, letterSpacing: '0.15em',
+        padding: '3px 8px',
+        background: 'rgba(0,0,0,0.7)',
+        border: '1px solid rgba(26,58,255,0.4)',
+        color: '#7aa4ff',
+        borderRadius: 2,
+      }}>
+        HLS ∙ ~5s
+      </div>
     </div>
   );
 }