Add JSON schema generation for kubeconform CRD validation

- ci/generate-schemas.sh extracts schemas from live cluster CRDs via kubectl
- Generated schemas committed to schemas/ for CI use
- Run `make schemas` to regenerate after CRD or K8s version changes
- validate-apps.sh and validate-clusters.sh check local schemas first
- CRD instances (Gateway, TLSRoute, Pooler, etc.) now validated instead of skipped
- CustomResourceDefinition meta-type still skipped (no schema exists upstream)

ci/validate-clusters.sh

@@ -3,7 +3,10 @@ set -euo pipefail
 
 KUBE_VERSION="1.33.7"
 
+SCHEMA_DIR="${SCHEMA_DIR:-schemas}"
+
 schema_args=(
+  -schema-location "$SCHEMA_DIR/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json"
   -schema-location "https://artifactapi.k8s.syd1.au.unkin.net/api/v1/remote/github_user/yannh/kubernetes-json-schema/master/{{.NormalizedKubernetesVersion}}-standalone{{.StrictSuffix}}/{{.ResourceKind}}{{.KindSuffix}}.json"
   -schema-location "https://artifactapi.k8s.syd1.au.unkin.net/api/v1/remote/github_user/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json"
 )