ShowCreditsController

Admin REST controller for per-show episode credit templates. Provides CRUD access to the credit definition list stored in show meta via ShowMeta::set_credits(). Ships in feature/membership-launch-cleanup. Auth: permission_callback_admin on all endpoints. Exposes GET /shows/{id}/credits and PUT /shows/{id}/credits. The GET endpoint accepts an optional episode_id query parameter that passes the result through the benecaster_credit_options filter, used by the episode editor to build the credit picker.