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On the LysozymeJet5 serial stills the default Gaussian profile-fit integrator (ProfileIntegrate2D) + reference scaling matched or beat whole-PixelRefine on every per-shell CC1/2 (overall 95.7% vs 91.9%), ISa (1.6 vs 1.2) and R-meas (98.5% vs 175%), with CCref a tie -- so PixelRefine has no remaining advantage. Reference-based per-image scaling is integrator-agnostic (IndexAndRefine::ReferenceIntensities builds a ScaleOnTheFly(experiment, reference) applied to any integrator's output), so the reference-dataset feature (CCref + reference scaling) is kept. Delete image_analysis/pixel_refinement/, GeomRefinementAlgorithmEnum:: PixelRefine and its gates, BraggIntegrationSettings::ProfileMultiplier (PixelRefine-only; R1 is shared and kept), and the -r pixelrefine / --profile-multiplier CLI. The inherited lessons (mean background, de-biased variance, tight-profile-loses / centroid floor, R-refinement futile) are folded into NEXTGEN_INTEGRATOR.md. NOTE: this transiently breaks the viewer build -- the committed viewer still references the removed enum and ProfileMultiplier. It is fixed in the next commit (the viewer feature work), held separate while the viewer UI is being tested. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>