feat: add Containerfile and compose.yaml for podman

Alpine-based image (59MB), source and config bind-mounted via
compose.yaml. Host networking for access to local Tor nodes.

Containerfile

@@ -0,0 +1,14 @@
+FROM python:3.13-alpine
+
+RUN pip install --no-cache-dir pyyaml>=6.0
+
+WORKDIR /app
+
+ENV PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONPATH=/app/src
+
+EXPOSE 1080
+
+ENTRYPOINT ["python", "-m", "s5p"]
+CMD ["-c", "/app/config/s5p.yaml"]