gt done now completes successfully even if the polecat's worktree is
deleted mid-operation by the Witness or another process.
Changes:
- Add FindFromCwdWithFallback() that returns townRoot from GT_TOWN_ROOT
env var when getcwd fails
- Update runDone() to use fallback paths and env vars (GT_BRANCH,
GT_POLECAT) when cwd is unavailable
- Update updateAgentStateOnDone() to use env vars (GT_ROLE, GT_RIG,
GT_POLECAT) for role detection fallback
- All bead operations are now explicitly non-fatal with warnings
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
f9ca7bb87b