chore: add tests for schema and API config mocking

- Added unit tests for schema loader, mocking Config variables and resolvers.
- Added unit tests for Zabbix API configuration, verifying constants derived from Config.
- Mocked relevant modules and filesystem behaviors to enable isolated testing.
- Optimized imports on all files and include this within a new .junie/guidelines.md file

src/execution/template_deleter.ts

@@ -1,4 +1,3 @@
-
 import {DeleteResponse} from "../schema/generated/graphql.js";
 import {
     ZabbixDeleteTemplateGroupsRequest,