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
- Remove all kubeconform skip lists — all resource types now have schemas

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