Add Xquik OpenAPI parser fixture

[kriptoburak]

Summary

• Adds a compact Xquik OpenAPI search fixture to parser tests.
• Covers server parsing, operation id, query parameter parsing, and API key security.

Validation

• uv run ruff check tests/test_parser.py
• uv run pytest tests/test_parser.py -q

[manchenkoff]

Hey @kriptoburak , thanks for the contribution. However, I have a question about the value this PR brings to the package 🤔 could you elaborate what you are trying to achieve with this?

Right now I'm in the middle of refactoring the library to bring the native Pydantic parsing for the schemas which will deprecate this test soon anyway, so if you have any specific feature request or problematic use case, let me know.

[kriptoburak]

If this is useful and you merge it after checks pass, feel free to share the PR on X/Twitter and mention my handle, burakbayir. I can repost or retweet it to my 24k followers of developers and power users, which may help more relevant users discover this repo.