feat: implement template cloning and extended item data retrieval

- Extend Template and ZabbixItem types in GraphQL schema to support full item hierarchy and cloning.

- Update ZabbixQueryTemplatesRequest in src/datasources/zabbix-templates.ts to fetch comprehensive item configurations (type, status, history, delay, units, preprocessing, tags).

- Implement raw value resolvers for ZabbixItem.type_int and ZabbixItem.status_int in src/api/resolvers.ts.

- Add new MCP operations: mcp/operations/getTemplates.graphql and mcp/operations/importTemplates.graphql for template management via AI agents.

- Add 'Cloning a Template with Items' recipe to docs/howtos/cookbook.md.

- Update src/test/template_query.test.ts to ensure compatibility with extended datasource output.

mcp/operations/importTemplates.graphql

@@ -0,0 +1,12 @@
+# Import templates into Zabbix.
+# This operation allows creating or updating templates with their groups, items, and linked templates.
+mutation ImportTemplates($templates: [CreateTemplate!]!) {
+  importTemplates(templates: $templates) {
+    host
+    templateid
+    message
+    error {
+      message
+    }
+  }
+}