UI: Add project selection in Create Kubernetes Cluster form (projectid supported by createKubernetesCluster API)

### The required feature described as a wish

ISSUE TYPE
* Improvement Request

COMPONENT NAME
~~~
UI, Kubernetes Service (CKS)
~~~

CLOUDSTACK VERSION
~~~
4.22.1.0
~~~

SUMMARY

The createKubernetesCluster API in 4.22.1.0 supports the `projectid` parameter
("Deploy cluster for the project"), and the API response includes `project` and
`projectid` fields:
https://cloudstack.apache.org/api/apidocs-4.22/apis/createKubernetesCluster.html

However, the "Add Kubernetes Cluster" form in the UI has no field to select a
project. Currently, deploying a CKS cluster into a project can only be
achieved either by calling the API directly (passing projectid), or by
switching the UI view to the specific project before creating the cluster.

There is no way to choose the target project directly from the cluster
creation form itself, unlike other resource creation flows in the UI. This is
inconsistent and inconvenient, especially for admins managing multiple
projects.

STEPS TO REPRODUCE
~~~
1. Log in to the CloudStack 4.22.1 UI Default View
2. Navigate to Compute > Kubernetes > Create Kubernetes Cluster
3. Observe there is no field/dropdown to select a project for the cluster
4. Compare with the createKubernetesCluster API, which accepts "projectid"
~~~

EXPECTED RESULTS
~~~
The "Add Kubernetes Cluster" form should include a project dropdown
(populated via listProjects), so the cluster and its resources are created
under the selected project — equivalent to passing projectid to the
createKubernetesCluster API.
~~~

Beginnen Sie mit dem Add Kubernetes Cluster-Formular in der CloudStack UI und prüfen Sie die Dokumentation zur createKubernetesCluster API, insbesondere projectid und die Projektfelder in ihrer Antwort. Verfolgen Sie, wie andere UI-Formulare Projekte mit listProjects befüllen. Erledigt ist die Aufgabe, wenn das Formular ein Projektauswahlfeld anbietet und beim Erstellen des Clusters die ausgewählte projectid übergibt.

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