Reconcile with #4539 (grok media account model mapping), now on main:
- handler/grok_media.go non-failover error path keeps both changes —
#4539's grokMediaScheduleModel(account, routingModel, nil) schedule
attribution and this branch's IsResponseCommitted guard
- auto-merged sections verified: routing/classify use #4539's routingModel,
video lookup owner-binding and no-failover semantics intact, ForwardGrokMedia
keeps mapping block (skipped for lookup endpoints via RequiresRequestBody),
empty-image failover, and video-status URL rewrite in order
shaw
14608dc6d4