Add @spaces.GPU decorator to analyze_video for GPU allocation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app.py

@@ -61,6 +61,7 @@ def normalize(arr):
     return (arr - mn) / (mx - mn) * 100
 
 
+@spaces.GPU
 def analyze_video(video_path):
     """Run TRIBE v2 inference and extract zone signals + composite engagement."""
     m = get_model()