Synthetic bold grows a glyph's outline in its own space, so a
non-uniform character Scale stretches it more along one axis. The patch
and layer bounds reserved it through mean_scale and could clip the
stretched side; they now reserve how far the bold reaches along x and y.
A run of solid fills grows its glyphs together in layer space by one
radius, which only matches when the bold stays round there: a bold glyph
whose matrix stretches or skews is no longer gathered into a run.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
