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/rke-machine-config.cattle.io/digitaloceanconfig_v1.json

@@ -0,0 +1,81 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "properties": {
+    "accessToken": {
+      "default": "",
+      "nullable": true,
+      "type": "string"
+    },
+    "apiVersion": {
+      "type": "string"
+    },
+    "backups": {
+      "default": false,
+      "type": "boolean"
+    },
+    "image": {
+      "default": "ubuntu-20-04-x64",
+      "nullable": true,
+      "type": "string"
+    },
+    "ipv6": {
+      "default": false,
+      "type": "boolean"
+    },
+    "kind": {
+      "type": "string"
+    },
+    "metadata": {
+      "type": "object"
+    },
+    "monitoring": {
+      "default": false,
+      "type": "boolean"
+    },
+    "privateNetworking": {
+      "default": false,
+      "type": "boolean"
+    },
+    "region": {
+      "default": "nyc3",
+      "nullable": true,
+      "type": "string"
+    },
+    "size": {
+      "default": "s-1vcpu-1gb",
+      "nullable": true,
+      "type": "string"
+    },
+    "sshKeyContents": {
+      "default": "",
+      "nullable": true,
+      "type": "string"
+    },
+    "sshKeyFingerprint": {
+      "default": "",
+      "nullable": true,
+      "type": "string"
+    },
+    "sshPort": {
+      "default": "22",
+      "nullable": true,
+      "type": "string"
+    },
+    "sshUser": {
+      "default": "root",
+      "nullable": true,
+      "type": "string"
+    },
+    "tags": {
+      "default": "",
+      "nullable": true,
+      "type": "string"
+    },
+    "userdata": {
+      "default": "",
+      "nullable": true,
+      "type": "string"
+    }
+  },
+  "type": "object"
+}