Adds interactive settings command to toggle workflow agents:
- Plan Researcher (workflow.research)
- Plan Checker (workflow.plan_check)
- Execution Verifier (workflow.verifier)
Updates plan-phase.md and execute-phase.md to check config before
spawning these agents. Flags still override config per-invocation.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>