brain_query and brain_read left no record of who read what; only capture
and governance edits reached the audit sink (OWASP MCP08).
One slog record per call: tool, principal, origin (static/jwt/unknown),
wing/hall when given, outcome, duration. Content is reduced to
content_bytes so the audit line never copies brain content.
Refs #144
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
