Children fan out from the parent's worktree HEAD and merge via a
generalized planning orchestrator (parent branch + children); child
roadblocks roll up to the parent review card.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Agent offloads out-of-scope work via SuggestImprovement; children run
automatically; new WaitingForChildren state; generalize planning's
parent/child machinery.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>