Adds step 10.5 to gsd-new-milestone that scans pending todos against the approved roadmap and tags matches with `resolves_phase: N` in their YAML frontmatter. Adds a `close_phase_todos` step to execute-phase that moves tagged todos to `completed/` when the phase completes — closing the loop automatically with no manual cleanup. Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>