Document verified Hugging Face checkpoint download

README.md

@@ -23,15 +23,23 @@ RGB observations and a navigation instruction.
 
 ## Download
 
-Download the checkpoint from the [GitHub release](https://github.com/yangyihui0502/ScaleNav/releases/tag/scalenav-v1).
 From the ScaleNav code repository:
 
 ```bash
+hf auth login
 python scripts/download_checkpoint.py --output checkpoints/scalenav
 ```
 
-This Hub repository provides the model card, architecture configuration and
-file checksums.
+The downloader uses a fixed Hugging Face revision and verifies each file's
+SHA-256. A [GitHub mirror](https://github.com/yangyihui0502/ScaleNav/releases/tag/scalenav-v1)
+is available with `--source github`.
+
+To download directly with the Hugging Face CLI:
+
+```bash
+hf download Yangyihui/ScaleNav --revision v1.0 --local-dir checkpoints/scalenav \
+  --include 'transformer/*' ar_model.pt train_meta.pt SHA256SUMS.json
+```
 
 Download the Wan VAE, text encoder and tokenizer using the
 [installation and checkpoint guide](https://github.com/yangyihui0502/ScaleNav#checkpoints).