docs: Add a description for the OpaCluster CRD (#843)

I more or less copied this from our other operators.

Author: lfrancke

CHANGELOG.md

@@ -9,6 +9,7 @@ All notable changes to this project will be documented in this file.
 - Added support for OPA `1.16.2`. `1.12.3` is now deprecated ([#838]).
 - BREAKING: Add required CLI argument and env var to set the image repository used to construct final product image names: `IMAGE_REPOSITORY` (`--image-repository`), eg. `oci.example.org/my/namespace` ([#830]).
 - Support `configOverrides` for `config.json` ([#818], [#831]).
+- Add a description for the `OpaCluster` CRD, which shows up in the generated CRD ([#843]).
 
 ### Changed
 
@@ -31,6 +32,7 @@ All notable changes to this project will be documented in this file.
 [#836]: https://github.com/stackabletech/opa-operator/pull/836
 [#838]: https://github.com/stackabletech/opa-operator/pull/838
 [#840]: https://github.com/stackabletech/opa-operator/pull/840
+[#843]: https://github.com/stackabletech/opa-operator/pull/843
 
 ## [26.3.0] - 2026-03-16
 

extra/crds.yaml

@@ -21,6 +21,10 @@ spec:
         description: Auto-generated derived type for OpaClusterSpec via `CustomResource`
         properties:
           spec:
+            description: |-
+              An OPA (Open Policy Agent) cluster stacklet. This resource is managed by the Stackable operator for OPA.
+              Find more information on how to use it and the resources that the operator generates in the
+              [operator documentation](https://docs.stackable.tech/home/nightly/opa/).
             properties:
               clusterConfig:
                 default:
@@ -1914,6 +1918,10 @@ spec:
         description: Auto-generated derived type for OpaClusterSpec via `CustomResource`
         properties:
           spec:
+            description: |-
+              An OPA (Open Policy Agent) cluster stacklet. This resource is managed by the Stackable operator for OPA.
+              Find more information on how to use it and the resources that the operator generates in the
+              [operator documentation](https://docs.stackable.tech/home/nightly/opa/).
             properties:
               clusterConfig:
                 default:

rust/operator-binary/src/crd/mod.rs

@@ -75,6 +75,9 @@ pub enum Error {
     )
 )]
 pub mod versioned {
+    /// An OPA (Open Policy Agent) cluster stacklet. This resource is managed by the Stackable operator for OPA.
+    /// Find more information on how to use it and the resources that the operator generates in the
+    /// [operator documentation](DOCS_BASE_URL_PLACEHOLDER/opa/).
     #[versioned(crd(
         group = "opa.stackable.tech",
         status = "OpaClusterStatus",