designTolerancePercent

Share of pixels allowed to differ between a fixture and its design reference before the fixture is reported as a mismatch. Unset by default, leaving viddik's own 5% — a design is drawn by a different rasterizer than Compose, so the golden threshold would fail on anti-aliasing alone. Becomes the viddik.designTolerancePercent system property.

Separate from tolerancePercent on purpose: that one measures rendering noise between two runs of the same code, this one measures how far the code is from its design.