Snapshot of the messy state: factored likelihood Terms 1+2+3 behind PR_* env flags (PR_INTENSITY/PR_SHAPE/PR_RECENTER) alongside the old per-pixel ShoeboxResidual, plus diagnostic scaffolding (PR_R0/R1/COV/FIX_R0/FIX_R/ ADAPT_R1/CENTROID/RECENTER) and the FACTORED_MODEL.md spec. Next commit makes Terms 1+2 the model and strips all of this. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>