support multipart bodies for HTTP QUERY, add tests & docs (RFC 10008 / OAS 3.2)

[mdrezuanislamridoy]

Summary

Adds end-to-end support and test coverage for the HTTP QUERY method (RFC 10008 / OpenAPI 3.2.0).

Most of the QUERY pipeline was already supported. This PR fixes the remaining curl generation issue and verifies the full flow with unit and E2E tests.

Changes

• Fix: Added QUERY to the multipart/form-data curl generation path so requests correctly use -F flags instead of -d.
• Unit tests:
  • Added curl generation tests for QUERY with:
    • No body
    • JSON body and headers
    • URI query strings
    • Multipart/form-data
    • No POST-specific bodyless behavior
  • Added selector coverage to ensure query: operations are parsed as method: "query".
  • Added GET/POST regression checks.
• E2E tests:
  • Added a real local Node HTTP server that echoes the received HTTP method.
  • Added an OpenAPI 3.2.0 fixture with a query operation.
  • Added Cypress coverage confirming:
    • QUERY renders correctly in the UI.
    • The browser actually sends QUERY to the server.
    • Generated curl uses -X QUERY, not GET or POST.
• Documentation:
  • Added docs/usage/http-query-method.md covering RFC 10008, OpenAPI usage, curl, CORS/preflight, and browser considerations.
  • Updated relevant configuration and CORS documentation.

Testing

• npm run test:unit - 875 passed, 0 failed
• ESLint - clean
• npm run build:core - successful
• Cypress - all 3 new QUERY E2E specs pass in Chrome 152 headless against the real local HTTP server

Limitations

• QUERY is only supported natively through OpenAPI 3.2.0. No vendor-extension fallback is provided for older OpenAPI versions.
• The full Cypress cy:ci suite was not run locally; only the new targeted QUERY spec was run. The full suite should be run in CI before merge.

Checklist

• Bug fix
• Improvement
• Non-breaking change
• Documentation updated
• Tests added
• Edge cases covered
• All new and existing unit tests pass

[masfiktalukdar]

Great feature. It should be must implemented