feat: add timecode to guest comments on share token page

Guest comments now capture the current video playback position
(timestamp) on submit, matching registered user comment behavior.
Shows "Comment at HH:MM:SS" preview above the Post button.

src/app/share/[token]/page.tsx

@@ -36,6 +36,7 @@ export default function SharePage() {
   const [commentText, setCommentText] = useState('');
   const [commentSubmitting, setCommentSubmitting] = useState(false);
   const [commentError, setCommentError] = useState<string | null>(null);
+  const [currentTime, setCurrentTime] = useState(0);
 
   // ── Load guest name from localStorage ───────────────────────────────────────
   useEffect(() => {
@@ -151,6 +152,7 @@ export default function SharePage() {
       const data = await shareLinksApi.postGuestComment(tokenParam, {
         guestName: guestName.trim(),
         content: commentText.trim(),
+        timestamp: currentTime > 0 ? currentTime : undefined,
       });
       setComments(prev => [...prev, data.comment]);
       setCommentsTotal(prev => prev + 1);
@@ -396,9 +398,11 @@ export default function SharePage() {
           {streamUrl ? (
             <div className="w-full max-w-6xl mx-auto" style={{ aspectRatio: '16/9', maxHeight: '85vh' }}>
               {isHls ? (
-                <video ref={videoRef} className="w-full h-full" controls playsInline />
+                <video ref={videoRef} className="w-full h-full" controls playsInline
+                  onTimeUpdate={e => setCurrentTime(e.currentTarget.currentTime)} />
               ) : (
-                <video ref={videoRef} src={streamUrl} className="w-full h-full" controls playsInline />
+                <video ref={videoRef} src={streamUrl} className="w-full h-full" controls playsInline
+                  onTimeUpdate={e => setCurrentTime(e.currentTarget.currentTime)} />
               )}
             </div>
           ) : !linkInfo?.asset.videoReady ? (
@@ -425,6 +429,14 @@ export default function SharePage() {
                 style={{ background: 'rgba(255,255,255,0.05)', color: 'var(--text)', border: '1px solid rgba(255,255,255,0.08)', outline: 'none' }}
               />
               {commentError && <p className="text-xs mt-1" style={{ color: '#F87171' }}>{commentError}</p>}
+              {currentTime > 0 && (
+                <div className="text-xs mb-2 flex items-center gap-1" style={{ color: '#A78BFA' }}>
+                  <svg className="w-3 h-3" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
+                    <path strokeLinecap="round" strokeLinejoin="round" d="M12 8v4l3 3m6-3a9 9 0 11-18 0 9 9 0 0118 0z" />
+                  </svg>
+                  Comment at {formatTimecode(currentTime, 30, currentTime)}
+                </div>
+              )}
               <div className="flex justify-end mt-2">
                 <button type="submit" disabled={commentSubmitting || !commentText.trim()}
                   className="flex items-center gap-1.5 text-xs px-3 py-1.5 rounded-lg transition-all"