Dockerize Django app with dev/beta/prod env config and uv.

Replace hardcoded settings with environment-driven config, add Docker
compose for local and production deploys, migrate from pip to uv, and
split Gitea workflows so PRs run tests only while master pushes deploy.

Dockerfile

@@ -0,0 +1,28 @@
+FROM python:3.12-slim
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    UV_COMPILE_BYTECODE=1 \
+    UV_LINK_MODE=copy \
+    UV_PROJECT_ENVIRONMENT=/app/.venv
+
+WORKDIR /app
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends libpq5 \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
+
+COPY pyproject.toml uv.lock ./
+RUN uv sync --frozen --no-dev
+
+COPY company_site ./company_site
+COPY scripts/docker-entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+WORKDIR /app/company_site
+
+EXPOSE 8000
+
+ENTRYPOINT ["/entrypoint.sh"]