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>

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build clean
+.PHONY: build clean schemas
 
 # Build a kustomization path to manifests directory
 # Usage: make build clusters/au-syd1/bootstrap
@@ -6,6 +6,10 @@ build:
 	@mkdir -p manifests/$(filter-out $@,$(MAKECMDGOALS))
 	@kustomize build --enable-helm $(filter-out $@,$(MAKECMDGOALS)) --output manifests/$(filter-out $@,$(MAKECMDGOALS))
 
+# Generate JSON schemas from CRDs and Kubernetes swagger spec (run manually, results committed)
+schemas:
+	@ci/generate-schemas.sh schemas
+
 # kubeconform
 kubeconform:
 	@ci/validate-apps.sh && \