🧮 Four-Point Probe — Simple Linear Fit
For each uploaded file: fits I = a·V + b (least squares), computes R = 1/a, then Rs = 4.53236 · R. Optionally applies a rectangular-geometry correction (Ossila table).
For each uploaded file: fits I = a·V + b (least squares), computes R = 1/a, then Rs = 4.53236 · R. Optionally applies a rectangular-geometry correction (Ossila table).