feat: implement smoketest and extend host provisioning with template linking

- Add runSmoketest mutation to automate end-to-end verification.

- Add SmoketestExecutor and HostDeleter to support automated testing and cleanup.

- Extend createHost and importHosts to allow linking templates by name or ID.

- Update docs/howtos/cookbook.md with new recipe steps and AI/MCP guidance.

- Update .junie/guidelines.md with new verification and deployment standards.

- Add src/test/template_link.test.ts and update existing tests to cover new functionality.

- Regenerate GraphQL types to match schema updates.

mcp/operations/runSmoketest.graphql

@@ -0,0 +1,14 @@
+# Run a complete smoketest: creates a template, host group, and host,
+# verifies their creation and linkage, and then cleans up everything.
+# Variables: hostName, templateName, groupName
+mutation RunSmoketest($hostName: String!, $templateName: String!, $groupName: String!) {
+  runSmoketest(hostName: $hostName, templateName: $templateName, groupName: $groupName) {
+    success
+    message
+    steps {
+      name
+      success
+      message
+    }
+  }
+}