AMRs for the final merged progenitor groups. Each panel shows individual GCs (points) with asymmetric age and metallicity uncertainties. Grey-shaded kernel-density contours highlight the main population distribution, and the orthogonal distance regression linear fit (dashed line) accounts for errors in both variables. The linear fits provide a visual diagnostic of the overall AMR trend within each progenitor; however, they should not be interpreted as physical enrichment rates, as the inferred slopes depend sensitively on the sampled age range.