Update admin theme/layout and refresh README details.

Align the project baseline with the latest admin interface styling and layout structure while documenting setup and usage updates in README.

apps/api/Dockerfile

@@ -0,0 +1,8 @@
+FROM python:3.12-slim
+WORKDIR /app
+ENV PYTHONPATH=/app
+COPY requirements-dev.txt .
+RUN pip install --no-cache-dir -r requirements-dev.txt
+COPY . .
+EXPOSE 8000
+CMD ["python", "scripts/docker_entrypoint.py"]