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)

schemas/postgresql.cnpg.io/failoverquorum_v1.json

@@ -0,0 +1,38 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "properties": {
+    "apiVersion": {
+      "type": "string"
+    },
+    "kind": {
+      "type": "string"
+    },
+    "metadata": {
+      "type": "object"
+    },
+    "status": {
+      "properties": {
+        "method": {
+          "type": "string"
+        },
+        "primary": {
+          "type": "string"
+        },
+        "standbyNames": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "standbyNumber": {
+          "type": "integer"
+        }
+      },
+      "type": "object"
+    }
+  },
+  "required": [
+    "metadata"
+  ],
+  "type": "object"
+}