Pull LFS checkpoints unconditionally on boot

The previous setup only ran `git lfs pull` when torch wasn't already
installed. On HF Spaces where torch is baked into the base image, the
checkpoint files remained as 132-byte LFS pointers, causing YOLO to
crash with `UnpicklingError: invalid load key, 'v'` after cropping.

Also guards handle_box_select against None input from cleared annotator.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app.py

@@ -9,7 +9,14 @@ def run(cmd, cwd=None):
     subprocess.check_call(cmd, shell=True, cwd=cwd)
 
 def setup_deps():
+    # Pull LFS content if the weights are still pointer files (a pointer is ~130 B;
+    # the real mouse_yolo.pt is ~6 MB). This must run regardless of whether torch
+    # is already installed, because HF base images ship with torch and would otherwise
+    # skip the pull below.
+    if os.path.getsize("checkpoints/mouse_yolo.pt") < 10_000:
+        run("git lfs install && git lfs pull", cwd=".")
     print(f"mouse_yolo.pt size: {os.path.getsize('checkpoints/mouse_yolo.pt')} bytes")
+
     # Use a flag to prevent infinite restarts
     if os.environ.get("HF_SPACE_BOOTSTRAPPED") == "1":
         return
@@ -28,7 +35,6 @@ def setup_deps():
     run("pip install torch==2.6.0 torchvision==0.21.0 torchaudio==2.6.0 --index-url https://download.pytorch.org/whl/cpu")
     run("pip install -e .", cwd="segment-anything-2")
     run("pip install gradio opencv-python-headless ultralytics matplotlib")
-    run("git lfs install && git lfs pull", cwd=".")  # assuming checkpoints/mouse_yolo.pt is tracked
 
     # Relaunch the script with an env flag to avoid looping
     print("♻️ Restarting app to apply changes...")
@@ -152,7 +158,7 @@ def load_frame(video_file, frame_idx):
 
 def handle_box_select(data):
     global selected_box
-    boxes = data.get("boxes", [])
+    boxes = (data or {}).get("boxes", [])
     if boxes:
         selected_box = boxes[0]
         return gr.update(interactive=True)