Modal magnitude R=hypot(a,b) with amplitude error and separate phase;
free-intercept ln R rate fit with per-interval rates, log-fit residual,
t* units and finite-positive check; spurious-pressure naming with raw rms;
INVALID_CONTROL vs CONTROL_SCREEN_FAIL (refined results kept), mixed-source
check, raw ratios to both controls; docs narrow the cubic-term scope,
startup and placement limitations. oracle.py still byte-identical.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>