Adds agent-beads-exist check to gt doctor: - Verifies witness/refinery beads exist for each rig - Verifies deacon/mayor beads exist in first rig - Supports --fix to create missing agent beads - Skips non-gt prefixes (beads library limitation) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>