Cross-cutting conventions for the Discogs API (api.discogs.com) that apply to every endpoint. Make sure to use this skill whenever a Discogs request touches general API behaviour rather than one specific resource — setting the mandatory User-Agent, handling rate limiting (X-Discogs-Ratelimit headers, 60/min authenticated vs 25/min unauthenticated), paginating list responses (page / per_page, Link header, pagination object), pinning an API version via the Accept header, returning JSONP, or interpreting HTTP status codes (200/201/204/401/403/404) and empty responses from Discogs.
