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>

README.md

@@ -229,6 +229,14 @@ Requires Python 3.13+ and [uv](https://astral.sh/uv). An NVIDIA, AMD, or Intel G
 
 ---
 
+## Getting Help
+
+- **[GitHub Discussions](https://github.com/sudolulo/winnow/discussions)** — questions, setup help, and general discussion
+- **[Wiki](https://github.com/sudolulo/winnow/wiki)** — setup guide, troubleshooting, and FAQ
+- **[Issues](https://github.com/sudolulo/winnow/issues)** — bugs and feature requests only
+
+---
+
 ## Attribution
 
 Based on [if_curator](https://github.com/ds-sebastian/if_curator) by Sebastian, licensed MIT.