Adds a third figure tracking plant.M/plant.C alongside the existing temperature/state plots, making the per-step mass changes (malt going in, water boiling off) visible. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01CgR9tPaSzFkAwRAUyeaaCD