Paper 57A: KPI-B Lite — Photometric Negative Control and Pipeline Calibration in PRIMER–COSMOS A reproducible pilot for tracer-turnover rejuvenation tests in Holosphere throughput cosmology

Paper 57A reports a single, fully reproducible KPI-B Lite pilot on PRIMER–COSMOS as a governance-grade negative control for the tracer-turnover (“galactic swirl”) explanation of apparent cosmic youth proposed in Paper 57. Because the public ASTRODEEP PRIMER paired catalogs do not provide full SED-based age/SFR decomposition, we use a deliberately minimal two-band surrogate: a blue-tail threshold on a survey-window–controlled residualized color (short–minus–long band) as a rejuvenation-like indicator. We test whether this indicator correlates with a local environment/load proxy defined by foreground neighbor counts, calibrating significance with a blocked permutation null that preserves the same tiling and binning structure used for residualization. In the executed run (N_used = 97,094; N_finite dC = 6,120; N_null = 2000), observed correlations are small and positive but consistently below the matched-null baseline, yielding no evidence of a non-null association for this proxy pairing. This null result is informative: it bounds the signal obtainable from generic two-band “blueness” under strict governance and motivates escalation to an explicitly two-component rejuvenation definition (old-substrate proxy ∧ recent-activity proxy) with explicit merger-cleaning once suitable morphology/close-pair screens are available. All tables and the single figure are regenerated from one appendix program and its emitted artifacts (CSV tables, per-object export, summary, and manifest).