ARED Vacuum Cylinder: Corrected Force Curve (2D)

This 2D companion to the 3D ARED exercise simulator drives the same Boyle's-law piston physics — P(x) = P_v0·V0/(V0+A·x), F(x) = n·(P_atm − P(x))·A — but replaces the 3D scene with a live, pannable and zoomable force-vs-stroke graph next to a piston/cylinder cross-section, and fixes a real bug found in the 3D engine: its piston area was too small to ever reach the 2,700 N (600 lbf) ISS spec constant its own bone-load model normalizes against, silently capping the achievable load fraction at about a third of what the model assumes is possible. The corrected area here lets the force curve genuinely reach that ceiling at near-maximal vacuum with both cylinders engaged, while every other equation — including the dose-response muscle and bone density trends from vacuum level, cylinder count, session duration and weekly frequency — stays identical to the 3D sim.