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>

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "winnow"
 version = "0.2.13"
-description = "Immich to Frigate training sets"
+description = "Selects diverse, high-quality photos from Immich as training data for Frigate face recognition and object classification."
 license = "AGPL-3.0-or-later"
 requires-python = ">=3.13"
 authors = [{ name = "Holden Salomon", email = "holden@arch.fyi" }]
@@ -9,6 +9,7 @@ keywords = ["immich", "frigate", "face-recognition", "training-data", "arcface",
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Intended Audience :: Developers",
+    "Intended Audience :: System Administrators",
     "License :: OSI Approved :: GNU Affero General Public License v3 or later (AGPLv3+)",
     "Programming Language :: Python :: 3.13",
     "Topic :: Scientific/Engineering :: Image Recognition",