The witness session was starting in the rig root (e.g., /gt/gastown)
instead of the witness directory (e.g., /gt/gastown/witness/rig).
This caused gt prime to detect the Mayor role instead of Witness role.
Now ensureWitnessSession uses the same pattern as ensureRefinerySession:
1. Try <rig>/witness/rig/ first (for rigs with worktree setup)
2. Fall back to <rig>/witness/ (for simpler setups)
3. Last resort: use rig root (shouldn't happen normally)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
5e093dadff