feat: init epub audit tool (distroless/python)

- Implemented 'audit_epubs.py' using standard libraries (zipfile, xml.etree) for high performance.
- Created optimized Dockerfile based on 'gcr.io/distroless/python3-debian12' for minimal security attack surface.
- Added strict metadata validation rules.
- Included CI/CD workflow for Gitea Actions.
- Added comprehensive README.md.

Dockerfile

@@ -0,0 +1,21 @@
+# Build Stage
+FROM python:3.11-slim-bookworm AS builder
+WORKDIR /app
+COPY audit_epubs.py .
+
+# Final Stage: Distroless
+FROM gcr.io/distroless/python3-debian12
+
+# OCI Labels
+LABEL org.opencontainers.image.title="EPUB Audit Tool" \
+      org.opencontainers.image.description="Outil d'audit de métadonnées de livres numériques EPUB (Distroless/Python)" \
+      org.opencontainers.image.authors="Maxime Killinger" \
+      org.opencontainers.image.source="https://gitea.killinger.fr/maxime.killinger/epub-audit" \
+      org.opencontainers.image.licenses="MIT"
+
+WORKDIR /app
+COPY --from=builder /app/audit_epubs.py .
+
+# Distroless python entrypoint is already python3
+# We just provide the script and default argument
+CMD ["audit_epubs.py", "/books"]