Add chart release instructions

Author: attilaedelenyi

README.md

@@ -45,6 +45,12 @@ See each chart's README for full configuration reference:
 - [`charts/ontoserver/README.md`](charts/ontoserver/README.md) — platform-specific examples (AKS, EKS, local k3d)
 - [`charts/ontoserver-extras/README.md`](charts/ontoserver-extras/README.md)
 - [`charts/ontoserver-indexer/README.md`](charts/ontoserver-indexer/README.md) — SNOMED CT and LOINC indexing examples
+- [`charts/README.md`](charts/README.md) — chart release and publishing instructions
+
+### Releasing Charts
+
+Maintainer-facing release instructions live in [`charts/README.md`](charts/README.md).
+Use that document for chart tag formats, workflow triggers, and post-release checks.
 
 ### ArgoCD Examples
 

charts/README.md

@@ -0,0 +1,54 @@
+# Helm Charts
+
+This directory contains the maintained Helm charts published from this repository:
+
+- [`ontoserver/`](./ontoserver/) - main Ontoserver chart
+- [`ontoserver-extras/`](./ontoserver-extras/) - optional Varnish and OpenTelemetry components
+- [`ontoserver-indexer/`](./ontoserver-indexer/) - one-shot indexing Job chart
+
+## Releasing Charts
+
+Charts are released from Git tags via GitHub Actions.
+
+Preferred distribution is the GitHub Pages Helm repository:
+
+```bash
+helm repo add ontoserver https://aehrc.github.io/ontoserver-deploy
+```
+
+Release tags must match the workflow triggers in `.github/workflows/release.yml`:
+
+- `ontoserver-vX.Y.Z`
+- `ontoserver-extras-vX.Y.Z`
+- `ontoserver-indexer-vX.Y.Z`
+
+Pushing one of those tags triggers the chart release workflow, which:
+
+- publishes the chart to the GitHub Pages Helm repository via `chart-releaser-action`
+- updates `artifacthub-repo.yml` on the `gh-pages` branch
+- pushes the packaged chart to `ghcr.io/aehrc` as a secondary OCI artifact
+
+Example:
+
+```bash
+git tag ontoserver-v0.1.0
+git push origin ontoserver-v0.1.0
+```
+
+After the first release, confirm:
+
+- GitHub Pages is enabled for the `gh-pages` branch
+- the new chart version appears in the Helm repo index
+- the corresponding `ghcr.io` package visibility is set as intended
+
+## Releasing Varnish Exporter
+
+The Varnish exporter image is released separately from `.github/workflows/release-varnish-exporter.yml`.
+
+Use a tag in this format:
+
+- `varnish-exporter-vX.Y.Z`
+
+That tag builds and publishes:
+
+- `ghcr.io/aehrc/varnish-exporter`