README: cross-link to NC extension yxma/gelsight-mini-pretrain-nc

README.md

@@ -92,6 +92,12 @@ Every row carries a `domain` column (`"real"` or `"sim"`) and a `markered` flag
 
 ➡️  **For a full per-subset breakdown** (intro, paper, license, processing recipe, sample grids, stats) see **[SOURCES.md](SOURCES.md)**.
 
+📦  **Need more data and OK with non-commercial use?**  A companion
+extension at **[`yxma/gelsight-mini-pretrain-nc`](https://huggingface.co/datasets/yxma/gelsight-mini-pretrain-nc)**
+adds GelSight Mini sources whose licenses (e.g. CC-BY-NC-4.0) aren't
+compatible with this commercial-friendly repo. Same schema, same pipeline,
+strictly additive. Load both and concatenate for the largest pool.
+
 ## TL;DR
 
 ```python