Add OCI image labels, issue template config, paths-ignore, and metadata fixes

- Dockerfile: ARG VERSION + OCI labels (title, description, source, licenses, version)
- release.yml: pass VERSION build-arg to all four image builds
- docker-publish.yml: extend paths-ignore to cover community files
- .github/ISSUE_TEMPLATE/config.yml: disable blank issues, link to Discussions and wiki
- README.md: add Getting Help section
- pyproject.toml: expand description; add System Administrators audience classifier

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -65,6 +65,12 @@ RUN chmod +x /app/entrypoint.sh
 FROM base-${TARGETARCH}-${VARIANT} AS runtime
 
 ARG VARIANT=gpu
+ARG VERSION=dev
+LABEL org.opencontainers.image.title="winnow" \
+      org.opencontainers.image.description="Selects diverse, high-quality photos from Immich as training data for Frigate face recognition and object classification." \
+      org.opencontainers.image.source="https://github.com/sudolulo/winnow" \
+      org.opencontainers.image.licenses="AGPL-3.0-or-later" \
+      org.opencontainers.image.version="${VERSION}"
 ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y --no-install-recommends \