Fetch LFS weights via HTTPS resolve URL instead of git-lfs

`git lfs pull` is unreliable on the HF Gradio SDK runtime (no .git dir
or no git-lfs binary), so checkpoint files stay as ~130 B pointers and
torch.load crashes with `invalid load key, 'v'`. Download the real
blobs directly from huggingface.co/.../resolve/main/... instead; the
redirect to the LFS CDN is followed automatically by urllib.

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

app.py

@@ -8,13 +8,30 @@ def run(cmd, cwd=None):
     print(f"▶ {cmd}")
     subprocess.check_call(cmd, shell=True, cwd=cwd)
 
+LFS_BLOBS = {
+    "checkpoints/mouse_yolo.pt": "https://huggingface.co/spaces/Daniel-F/mouse-behavioral-study/resolve/main/checkpoints/mouse_yolo.pt",
+    "checkpoints/nose_detector.pth": "https://huggingface.co/spaces/Daniel-F/mouse-behavioral-study/resolve/main/checkpoints/nose_detector.pth",
+    "checkpoints/sam2_hiera_small.pt": "https://huggingface.co/spaces/Daniel-F/mouse-behavioral-study/resolve/main/checkpoints/sam2_hiera_small.pt",
+}
+
+def _fetch_lfs_blobs():
+    # The repo's .pt/.pth files are stored via Git LFS. On the HF Spaces runtime
+    # `git lfs pull` is unreliable (no .git dir and/or no git-lfs binary), so we
+    # download the resolved LFS blobs over HTTPS. A pointer file is ~130 B; real
+    # weights are multi-MB, so size < 10 KB means we still have the pointer.
+    import urllib.request
+    for path, url in LFS_BLOBS.items():
+        size = os.path.getsize(path) if os.path.exists(path) else 0
+        if size >= 10_000:
+            continue
+        print(f"⬇ fetching {path} from {url}")
+        tmp = path + ".part"
+        urllib.request.urlretrieve(url, tmp)
+        os.replace(tmp, path)
+        print(f"   → {os.path.getsize(path)} bytes")
+
 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=".")
+    _fetch_lfs_blobs()
     print(f"mouse_yolo.pt size: {os.path.getsize('checkpoints/mouse_yolo.pt')} bytes")
 
     # Use a flag to prevent infinite restarts