fix: remove duplicate Helm chart page and fix MDX parse error

Delete helm/k8s_reporter.mdx (hand-crafted, stale at v2.2.0) in favour
of helm/k8s_reporter.md which is auto-generated by the update-cli-docs
workflow. Escape <instance_name> with backticks to fix the MDX parser.

Permanent upstream fix tracked in kosli-dev/cli#853.

Author: dangrondahl

helm/k8s_reporter.md

@@ -158,7 +158,7 @@ If you already run [cert-manager's trust-manager](https://cert-manager.io/docs/t
 | customCA.enabled | bool | `false` | enable mounting a corporate/custom CA bundle into the trust store |
 | customCA.key | string | `"ca.crt"` | key within the Secret that holds the PEM-formatted CA certificate (single cert or multi-cert PEM bundle) |
 | customCA.secretName | string | `""` | name of an existing Secret in the same namespace containing the CA bundle |
-| env | object | `{}` | map of plain environment variables to inject into the reporter container. For a single-tenant Kosli instance, set KOSLI_HOST to https://<instance_name>.kosli.com. |
+| env | object | `{}` | map of plain environment variables to inject into the reporter container. For a single-tenant Kosli instance, set KOSLI_HOST to `https://<instance_name>.kosli.com`. |
 | extraEnvVars | list | `[]` | additional environment variables to inject into the reporter container. List of {name, value} or {name, valueFrom} entries, rendered verbatim into the container env. Supports plain values and valueFrom (secretKeyRef / configMapKeyRef). Note: entries here are appended after the chart's own env entries; on duplicate names the later entry wins. |
 | extraVolumeMounts | list | `[]` | additional container-level volumeMounts for the reporter container. Rendered verbatim into the container spec alongside the chart's own mounts. |
 | extraVolumes | list | `[]` | additional Pod-level volumes to attach to the reporter pod. Rendered verbatim into the Pod spec alongside the chart's own volumes. Use together with `extraVolumeMounts` to mount Secrets, ConfigMaps, or other volumes into the container. |