feat: Gradio demo app, DeBERTa Colab notebook, updated smoke test results (Day 13)

Add Colab notebooks: emotion classifier + corpus annotation (Day 12)

Day 3: proper Colab ipynb notebook for FAISS build

Day 3: FAISS index builder notebook for Colab A100

Day 1: data pipeline, session tracker, query router, adversarial probes, Colab training notebooks