Add SFT LLaMA3 GPU demo notebook and skip TPU CI run

Author: katjasrz

.github/workflows/run_jupyter_notebooks.yml

@@ -84,7 +84,7 @@ jobs:
 
           for notebook in "$MAXTEXT_NOTEBOOKS_ROOT"/{sft,rl}*.ipynb; do
             filename=$(basename "$notebook")
-            if [[ "$filename" == "sft_qwen3_demo.ipynb" ]]; then
+            if [[ "$filename" == "sft_qwen3_demo.ipynb" || "$filename" == "sft_llama3_demo_gpu.ipynb" ]]; then
               echo "Skipping $filename"
               continue
             fi

.gitignore

@@ -83,6 +83,8 @@ target/
 
 # Jupyter Notebook
 .ipynb_checkpoints
+.jupyter/
+.local/share/jupyter/
 
 # IPython
 profile_default/