A stills reflection recorded at partiality p carries a systematic intensity error ~(dp/p) that is
proportional to <I> and grows as p falls; plain counting sigma misses it, so strong low-p partials
are over-trusted in the merge. Add sigma^2 += (c*<I>*(1-p))^2 in MergeOnTheFly::CorrectedSigma - the
stills-partiality analog of the existing rotation --capture-uncertainty term ((1-captured_fraction)*I
in RotationScaleMerge). Inert when partiality==1 (no --still-partiality), and gated on a real
systematic (error_model_b > 1, i.e. ISa < 1) so it fires on strong/medium stills but auto-skips weak
counting-limited data where it would only over-concentrate the merge and hurt. Opt-in via
--partiality-uncertainty <c> (default 0; ~2.5 recommended with --still-partiality).
Prototyped (Python replica of the merge): lyso8 CC1/2 +1.7, CCref +4.8, R-free -0.023; LOV CCref +2;
harmful on weak OCP (hence the b>1 gate). Full in-binary validation across all serial targets pending.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 4.8
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