Simplify Athena runtime and document current architecture

platform/llama-dashboard/Dockerfile

@@ -0,0 +1,14 @@
+FROM python:3.13-slim
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1
+
+WORKDIR /app
+COPY app.py /app/app.py
+
+RUN useradd --uid 10020 --create-home --shell /usr/sbin/nologin dashboard
+
+USER 10020:10020
+EXPOSE 8099
+
+CMD ["python", "/app/app.py"]