Add Xquik OpenAPI ingestion example

[kriptoburak]

Summary

Adds a concrete Xquik example to the OpenAPI ingestion docs. Xquik exposes an OpenAPI 3.1 spec at https://xquik.com/openapi.json and uses the x-api-key header for API key authentication, so it fits the existing remote OpenAPI and API key examples.

Validation

• Confirmed https://xquik.com/openapi.json returns HTTP 200 with JSON.
• Checked the public OpenAPI security scheme for the x-api-key header.
• Ran git diff --check.

Duplicate Check

• Searched all-state PRs and issues for Xquik and xquik.com references before opening this PR.

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Summary by cubic

Add an Xquik example to the OpenAPI ingestion docs and refine wording around OpenAPI 3.1 compatibility. The example loads https://xquik.com/openapi.json, uses the x-api-key header with Python and UTCP manual_call_templates, and notes that only compatible 3.1 specs are supported and 3.1-specific features should be verified.

^{Written for commit c01cf65. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 1 file

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[kriptoburak]

Addressed the OpenAPI version consistency note in 456ad7e by updating the intro and multi-format support section to include OpenAPI 3.1 alongside 2.0 and 3.0.

Validation:

• git diff --check
• Public text scan for blocked terms
• Checked the doc no longer advertises only OpenAPI 2.0/3.0 support

[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[kriptoburak]

Addressed the follow-up compatibility note in the latest commit by removing the overbroad full OpenAPI 3.1 compatibility claim.

The doc now distinguishes full OpenAPI 2.0/3.0 compatibility from compatible OpenAPI 3.1 specifications and tells users to verify 3.1-specific schema features against the converter.

Validation:

• git diff --check
• Public text scan for blocked terms
• Checked the overbroad 3.1 compatibility wording is gone