fix(fonts): compress Petaluma barlineFinal thick stroke to balance with thin

Petaluma's thick:thin stroke ratio for the final barline (U+E032) was ~5:1,
noticeably wider than Bravura's ~3.5:1. Step 2c in the GrigsonPetaluma
preprocessing pipeline now scales the thick contour's x extent to a 3.75:1
ratio (xscale=0.75), reducing the advance width from 401 to 336 units.

Author: nelstrom