docs(groot): use literal HF repo IDs for dataset/policy repo_id

Public-facing Hub references (--dataset.repo_id, --policy.repo_id) shown as
concrete IDs; local-only values ($OUTPUT_DIR, $JOB_NAME) stay as placeholders.

docs/source/groot.mdx

@@ -80,7 +80,7 @@ Here's a complete training command for finetuning the base GR00T model on your o
 export BASE_MODEL=nvidia/GR00T-N1.7-3B
 
 uv run lerobot-train \
-  --dataset.repo_id=$DATASET_ID \
+  --dataset.repo_id=sreetz-nv/so101-clean-up-vials-into-rack-50_20260628_131121 \
   --dataset.image_transforms.enable=true \
   --policy.type=groot \
   --policy.device=cuda \
@@ -93,7 +93,7 @@ uv run lerobot-train \
   --policy.use_bf16=true \
   --policy.use_flash_attention=true \
   --policy.push_to_hub=true \
-  --policy.repo_id=$REPO_ID \
+  --policy.repo_id=sreetz-nv/so101-clean-up-vials-into-rack-50-groot-n17-relact-bs64-20k-20260628_johnny_42 \
   --seed=42 \
   --batch_size=64 \
   --steps=20000 \