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/importUserRights.graphql

@@ -0,0 +1,45 @@
+# Source: https://www.zabbix.com/documentation/7.4/en/manual/api/reference/usergroup/create
+
+### Query
+```graphql
+mutation ImportUserRights($input: UserRightsInput!, $dryRun: Boolean!) {
+  importUserRights(input: $input, dryRun: $dryRun) {
+    userGroups {
+      id
+      name
+      message
+    }
+    userRoles {
+      id
+      name
+      message
+    }
+  }
+}
+```
+
+### Variables
+```json
+{
+  "dryRun": true,
+  "input": {
+    "userGroups": [
+      {
+        "name": "New User Group",
+        "hostgroup_rights": [
+          {
+            "name": "Zabbix servers",
+            "permission": "READ"
+          }
+        ]
+      }
+    ],
+    "userRoles": [
+      {
+        "name": "New Role",
+        "type": 1
+      }
+    ]
+  }
+}
+```