Add support for the HTTP QUERY method (RFC 10008)

Request:
Add QUERY as a supported HTTP method in (1) External API Request function stacks, for calling third-party QUERY-enabled APIs, and (2) custom API endpoint definitions, so Xano-hosted endpoints can accept QUERY requests natively.

Why:
RFC 10008 (published June 2026) standardizes QUERY as a safe, idempotent method that carries a request body — unlike GET, which isn't meant to carry one, and unlike POST, which isn't safe/idempotent/cacheable. Two concrete Xano use cases:

  1. External API Request function: Some third-party APIs (search, filtering, data query providers) are starting to expose QUERY endpoints. The External API Request function currently only exposes a fixed set of methods (GET/POST/PUT/PATCH/DELETE); there's no way to send a request with method QUERY short of hoping a generic/custom-method override exists.

  2. Custom endpoint definitions: For complex filter/search endpoints (e.g. dashboard queries against large Postgres-backed workspaces), POST is currently used as a workaround since GET can't carry a JSON filter body reliably across proxies/browsers. This misrepresents intent (POST implies mutation) and blocks correct HTTP caching. Native QUERY support would let these endpoints be marked safe/idempotent and cacheable, matching actual semantics.

Minimal implementation ask:

  • Allow QUERY as a selectable method in External API Request.

  • Allow QUERY as a method option when defining custom API endpoints (alongside GET/POST/etc.), with body support like POST.

  • Respect Content-Type requirement per spec (reject if missing/inconsistent).