List content sources available for dynamic slides and tickers

Lists the workspace's content sources (id, name, adapterType, lastFetchedAt, isEnabled, and health: Healthy, Degraded after 1-2 failed fetches in a row or Failing after 3 or more, with lastError in plain words, consecutiveFailures and lastSuccessAt). Check health before building a slide on a source. Use this to pick a ticker source (PATCH /v1/slideshows/{id} with ticker.sourceIds) or a data feed for a dynamic slide (PATCH /v1/slides/{id} with sourceId).