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.

src/test/template_query.test.ts

@@ -37,7 +37,10 @@ describe("Template Resolver", () => {
         expect(zabbixAPI.post).toHaveBeenCalledWith("template.get", expect.objectContaining({
             body: expect.objectContaining({
                 method: "template.get",
-                params: {}
+                params: expect.objectContaining({
+                    output: "extend",
+                    selectItems: "extend"
+                })
             })
         }));
     });