작동 방식
Population sets the base scale. Prosperity (×0.5 / ×1 / ×2) and magic level (×0.5 / ×1 / ×2) modify the gold-piece purchase limit and trade counts.
Trade demographics use rough historical fractions of medieval populations — 60% farmers, ~1% blacksmiths, etc.
Use as a starting point for session prep; tweak counts manually for plot-specific NPCs.