SlugTextBatch.add() scaled em-unit glyph outlines by the raw DWG
`height` value, but glyph ink only reaches capHeightEm (~0.74 em) of
the em box. Rendered cap height ended up ~26% short of spec (e.g. a
3.6-height TABLE cell text rendered at ~2.68), while the canvas-sprite
fallback already corrected for this via measured ascent. Divide by
capHeightEm so both paths agree.
Rebuilds dist2 (was stale since before the Entity selection/Property
Inspector/Layer panel work landed).
