Each log_*.json now carries a "Config" key (the full server config) and
a "PlantParams" list of {t, params} entries — one per step transition —
so offline analysis tools have the PID gains and plant model that were
active at every point of the run without having to cross-reference a
separate config file.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>