Add JSON schema generation for kubeconform CRD validation (#212)

## Summary
- New `ci/generate-schemas.sh` script that generates JSON schemas from three sources:
  1. Live cluster CRDs via `kubectl get crds`
  2. Offline CRD manifests (ArgoCD v3.3.2, Gateway API v1.5.1)
  3. Kubernetes v1.33.7 swagger spec for native types
- Schemas follow Datree catalog convention (`<group>/<Kind>_<version>.json`)
- `validate-apps.sh` and `validate-clusters.sh` check local schemas first, falling back to remote
- Fixes TLSRoute (and other CRD) schema validation failures in kubeconform

## Sources
- ArgoCD: `artifactapi.../argoproj/argo-cd/refs/tags/v3.3.2/manifests/ha/install.yaml`
- Gateway API: `artifactapi.../kubernetes-sigs/gateway-api/releases/download/v1.5.1/standard-install.yaml`
- Kubernetes: `artifactapi.../kubernetes/kubernetes/refs/tags/v1.33.7/api/openapi-spec/swagger.json`

Reviewed-on: #212
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

ci/validate-apps.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"
 )
@@ -18,6 +21,6 @@ while IFS= read -r -d "" k; do
         -summary \
         -output pretty \
         -verbose \
-        -skip CustomResourceDefinition,GpuDevicePlugin,LBNodeAgent,ServiceGroup \
+        -skip CustomResourceDefinition \
         "${schema_args[@]}"
 done < <(find apps/overlays -name kustomization.yaml -print0)