Add missing type annotations

app.py

@@ -19,7 +19,7 @@ model = Gemma3ForConditionalGeneration.from_pretrained(
 )
 
 
-def downsample_video(video_path):
+def downsample_video(video_path: str) -> list[tuple[Image.Image, float]]:
     vidcap = cv2.VideoCapture(video_path)
     fps = vidcap.get(cv2.CAP_PROP_FPS)
     total_frames = int(vidcap.get(cv2.CAP_PROP_FRAME_COUNT))