Document a community Helm installation path for Glance

### Description

Would a short community Kubernetes installation section fit in the README?

I read the Docker setup and configuration guide, and found the earlier Helm chart request in #321. I couldn't find a Kubernetes installation walkthrough in the current documentation. I'm proposing a documentation contribution, with the chart maintained externally.

I maintain HelmForge and recently added a [Glance chart](https://github.com/helmforgedev/charts/tree/main/charts/glance). For this app, the useful parts of a Kubernetes guide are fairly small: mounting `glance.yml` from a ConfigMap without interpreting its custom-api Go templates, keeping login/widget credentials in Secrets, and preserving the session-signing key when a Pod is replaced. The chart uses the upstream image and does not mount the Docker socket or give the dashboard a Kubernetes API token.

I can open a PR showing a minimal Helm installation and how to supply an existing configuration and credentials, with a link to the [full chart guide](https://helmforge.dev/docs/charts/glance). It would identify HelmForge as a community option and direct chart-specific support to our repository. That also keeps the README from having to track all of our values.

Would that be useful, and would you prefer it in the README or as a separate page under `docs/`?

Start with the README's existing Docker setup and configuration guide, then review the linked HelmForge chart and its full chart guide. Decide whether the walkthrough belongs in the README or under docs/, and document a minimal community Helm installation using an existing configuration and credentials. Done means the guide covers the ConfigMap, Secrets, session-signing key, chart link, and chart-specific support location.

Written by the indexing model from the issue text.