Under the hood
Resuming a turn with no new prompt now skips an unnecessary model call in headless and SDK use.
Headless/SDK turn processing now computes a hasPrompt flag, false when the turn's prompt argument is an array with no elements. When an orphaned permission can't be applied and there is no prompt and no deferred tool use, the turn now ends without a model call, logging "Orphaned permission could not be applied and the turn has no prompt: ending the turn without a model call" and firing a telemetry event. This treats a "resume the turn, no new prompt" request as an empty prompt rather than a real one.