When a step is expanded (e.g., implement -> implement.draft, implement.refine-1, etc.), any steps that depended on the original step should now depend on the last step of the expansion. Call UpdateDependenciesForExpansion after both expand and map operations. Fixes gt-8tmz.3 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>