Closes #144 (audit line per tools/call) and #145 (origin/written_by stamped on every model-reachable write, surfaced in brain_query/brain_get). Passed pr-gatekeeper after four rounds of adversarial review, verified by execution: #147 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Co-authored-by: Mathias <mthbqv@gmail.com>