Fix LangSAM API: pass lists instead of bare string to predict()

The updated LangSAM API expects predict([image], [text]) with lists.
Passing a bare string caused it to iterate over characters (e.g.
"bear" -> ["b","e","a","r"]), breaking mask prediction entirely.
Also handles the new list[dict] return format and guards against
empty mask results.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: vsc38511

gaussctrl/gc_pipeline.py

@@ -148,8 +148,11 @@ def render_reverse(self):
             if self.config.langsam_obj != "":
                 langsam_obj = self.config.langsam_obj
                 langsam_rgb_pil = Image.fromarray((rendered_rgb.cpu().numpy() * 255).astype(np.uint8))
-                masks, _, _, _ = self.langsam.predict(langsam_rgb_pil, langsam_obj)
-                mask_npy = masks.clone().cpu().numpy()[0] * 1
+                # The new LangSAM API expects lists; passing a bare string causes it to
+                # iterate over characters (e.g. "bear" -> ["b","e","a","r"]), breaking batching.
+                results = self.langsam.predict([langsam_rgb_pil], [langsam_obj])
+                result_masks = results[0]["masks"]  # new API returns list[dict]
+                mask_npy = result_masks[0] * 1 if len(result_masks) > 0 else None
 
             if self.config.langsam_obj != "":
                 self.update_datasets(cam_idx, rendered_rgb.cpu(), rendered_depth, latent, mask_npy)