NTE per-axis signature table: figure (10 single-study series + 2 artifact checks)

Companion figure to the transition-ladder NTE atlas: per-axis linear expansion coefficients for 10 single-study confident NTE series grouped by signature class (isotropic, anisotropic smooth, transition redistribution), plus a separation plot locating the two artifact-check series (Eu-MOF 2024, GaMo4Se8 sg44 2022) outside the clean clusters.