### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

Installing `oci://ghcr.io/berriai/litellm-helm` with no `image.tag` override fails with `ImagePullBackOff`. The chart's default renders an image tag that is **not published** to `ghcr.io/berriai/litellm-database`.

## Root cause

`templates/deployment.yaml` and `templates/migrations-job.yaml` both default the tag to `main-<AppVersion>`:

```yaml image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default (printf "main-%s" .Chart.AppVersion) }}" ```

For chart 1.86.2 (`AppVersion: 1.86.2`) this renders `ghcr.io/berriai/litellm-database:main-1.86.2`, which returns **404**. The registry has the plain `1.86.2` tag (and `main-stable`), but not `main-1.86.2`.

## This is systemic across recent stable releases

Anonymous manifest checks on `ghcr.io/berriai/litellm-database`:

| Chart version | `main-<ver>` (default) | `<ver>` (plain) | |---|---|---| | 1.84.0 / 1.84.1 / 1.84.3 | 404 | 200 | | 1.85.0 / 1.85.1 / 1.85.2 | 404 | 200 | | 1.86.1 / 1.86.2 | 404 | 200 |

The published `1.86.2` tag and `main-stable` resolve to the **same digest** (`sh…