Relay the service's CDM calls to the client, accept the service's allowed identity config (for example ESN/Kpe/Kph), add the server_vault grant and a lent server-device mode that reads keys only from vaults and returns no login cache. Also fixes the proxied certificate fetch, Base64 Widevine licences, an answered call that stayed pending and a missing default quality.
api-only/remote-only serve now authenticates every serve.users key (str-coerced), not just api_secret, so per-user service allowlists apply. RemoteClient tries X-Secret-Key then X-Api-Key on 401 (sticky winner); remote_services.auth_headers prepends extra header names to the defaults.
Adds GET /api/download/jobs/{job_id}/events with snapshot, status, progress and terminal events, query-param auth for EventSource in both serve modes, atomic progress-file writes, and stream-safe CORS and compression middleware.