A `dump-font-atlas` subcommand renders a dat Font's fg/bg atlases (alpha as
luminance) plus a sample string composited exactly the way DrawStringDat does
it (outline + fill, integer-snapped). Used to reproduce the glyph-baseline
jitter offline (fractional-origin bug vs the fix) without launching the client.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
