Add opt-in mechanism to chain discuss → plan → execute automatically
via Task() subagents, eliminating manual /clear + paste overhead.
- Add `--auto` flag to discuss-phase and plan-phase commands
- Add `workflow.auto_advance` config toggle (default: false)
- Add auto_advance step to discuss-phase workflow (spawns plan-phase)
- Add step 14 to plan-phase workflow (spawns execute-phase)
- Add auto_advance toggle to /gsd:settings
Chain stops gracefully on INCONCLUSIVE, CHECKPOINT, or verification
failures. No work lost — artifacts persist at each step.
Closes#541
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
ed1768404c