HEAD & QUERY methods

Sources can now accept HEAD and QUERY requests. Like GET, both are opt-in — enable them per source in Source Configuration > Advanced Source Configuration, or per request with the x-hookdeck-allow-methods query parameter.

HEAD behaves like GET: no request body, and the request ID is returned in the x-hookdeck-request-id response header since a HEAD response carries no body. QUERY carries a body like POST, so its body is preserved on ingestion and delivery, and body signature verification works normally.