forked from 1b-agent/opencadstudio-upstream
Consolidates 21 occurrences of identical Color literals scattered across widgets.rs and mod.rs into 9 named constants (COMBO_BG, COMBO_HOVER_BG, COMBO_OPEN_BG, COMBO_BORDER, COMBO_ACTIVE_BORDER, COMBO_ARROW, SWATCH_BORDER, TIP_BG, HIST_INACTIVE_BG). -85 net lines, zero behaviour change.