#221 Replay: Add parent-child workflow reconciliation in reports

## Problem No visual tree of parent/child workflows in replay output. No validation that child statuses match parent expectations. ## Current State - Child workflows execute correctly - Events stored under workflow_run_id - No automatic parent↔child reconciliation ## Impact - Distributed workflow debugging difficult - No visibility into full execution tree - Manual correlation required ## Solution 1. Add --include-children flag to replay CLI 2. Build workflow execution tree in report 3. Validate child completion statuses 4. Show hierarchical view in output ## Effort: Small