feat: add Zabbix 7.4 documentation samples and importHostGroups MCP tool

This commit introduces a comprehensive set of GraphQL query and mutation samples based on the official Zabbix 7.4 API documentation, along with testing and automation improvements.

Changes:

- Documentation:

  - Added 21 GraphQL sample files in docs/queries/from_zabbix_docs/ covering various Zabbix API operations.

  - Updated docs/howtos/cookbook.md with a new recipe for executing these documentation samples.

- AI & MCP:

  - Added mcp/operations/importHostGroups.graphql to enable host group import via MCP tools.

- Testing:

  - Added src/test/zabbix_docs_samples.test.ts to automatically validate all documentation samples against the GraphQL schema.

docs/queries/from_zabbix_docs/importTemplates.graphql

@@ -0,0 +1,32 @@
+# Source: https://www.zabbix.com/documentation/7.4/en/manual/api/reference/template/create
+
+### Query
+```graphql
+mutation ImportTemplates($templates: [CreateTemplate!]!) {
+  importTemplates(templates: $templates) {
+    templateid
+    host
+    message
+  }
+}
+```
+
+### Variables
+```json
+{
+  "templates": [
+    {
+      "host": "New Template 1",
+      "groupNames": ["Templates/Operating systems"],
+      "items": [
+        {
+          "name": "Custom item",
+          "key": "custom.item",
+          "value_type": 3,
+          "history": "90d"
+        }
+      ]
+    }
+  ]
+}
+```