operator: if oidc auth changes, the configmap updates, but the service does not reload

[mangelajo]

When OIDC configuration changes in the operator, the related configmap gets updated,
but the controller does not reload this information.

We need to make the jumpstarter-controller restart/reload this information.

[ambient-code]

Fix PR: #438

The root cause is that the controller loads its configuration (including OIDC auth) once at startup from the jumpstarter-controller ConfigMap (in cmd/main.go via config.LoadConfiguration()). When the operator updates the ConfigMap, the controller pods are not restarted, so they continue using the stale configuration.

The fix adds a SHA-256 hash of the ConfigMap content as a pod template annotation (jumpstarter.dev/configmap-sha256) on the controller deployment. When the ConfigMap content changes, the hash changes, which updates the pod template annotation and triggers a Kubernetes rolling restart. This is the same pattern already used in the Helm chart (configmap-sha256 annotation).