reference controller in architecture docs

docs/contributor/01-architecture.md

@@ -32,6 +32,7 @@ Apart from the custom resources, Lifecycle Manager uses also Kyma, Manifest, and
 
 * [Kyma controller](../../internal/controller/kyma/controller.go) - reconciles the Kyma CR which means creating Manifest CRs for each Kyma module enabled in the Kyma CR and deleting them when modules are disabled in the Kyma CR. It is also responsible for synchronising ModuleTemplate CRs between KCP and Kyma runtimes.
 * [Manifest controller](../../internal/controller/manifest/controller.go) - reconciles the Manifest CRs created by the Kyma controller, which means, installing components specified in the Manifest CR in the target SKR cluster and removing them when the Manifest CRs are flagged for deletion.
+* [Mandatory Modules controller](02-controllers.md/#mandatory-modules-controllers) - reconciles the mandatory ModuleTemplates with the label `operator.kyma-project.io/mandatory-module`, selecting the highest version if duplicates exist. It translates ModuleTemplates to Manifest CRs linked to the Kyma CR, ensuring changes propagate. For removal, a deletion controller marks related Manifests, removes finalizers, and deletes the ModuleTemplate.
 * [Purge controller](../../internal/controller/purge/controller.go) - reconciles the Kyma CRs that are marked for deletion longer than the grace period, which means purging all the resources deployed by Lifecycle Manager in the target SKR cluster.
 * [Watcher controller](../../internal/controller/watcher/controller.go) - reconciles the Watcher CR which means creating Istio Virtual Service resources in KCP when a Watcher CR is created and removing the same resources when the Watcher CR is deleted. This is done to configure the routing of the messages that come from the watcher agent, installed on each Kyma runtime, and go to a listener agent deployed in KCP.