[EE-3024] subscription support evidence

[thomaschaplin]

This is to address some comments made in #48 about lack of subscription support.

This pull request adds comprehensive support and documentation for GraphQL subscriptions to the graphQlQueryToJson library, along with extensive test coverage and clarification of current limitations. The most important changes are grouped below:

Subscription Support and Documentation:

• Added a new section to the README.md with usage examples for GraphQL subscriptions, including basic subscriptions, subscriptions with variables/arguments, aliases, and enums. The API reference was updated to clarify that the query parameter now accepts subscription strings.
• Added a "Limitations" section to the documentation detailing unsupported features such as named and inline fragments, and the handling of directives (parsed but ignored).

Test Coverage:

• Added a new describe("Subscriptions", ...) block to src/test/full_functionality.spec.ts with thorough test cases covering simple subscriptions, arguments, aliases, enums, nested objects, directives, and error handling for unsupported fragments.
• Added corresponding subscription example tests to src/test/readme_examples.spec.ts to ensure README examples are validated by tests.

Minor Improvements:

• Added an ESLint directive to suppress console warnings in scripts/updateTestCoverage.js.

[rickschubert]

Great!

Do you think it would be okay to merge my PR in first though? I don't have access to that fancy AI, meaning my workflow is a lot more manual. I have a couple of changes in that PR which might affect your PR -- I assume it would be easy on your end but harder for me 😬

[thomaschaplin]

@rickschubert please re-review