Add ChrFont, a reader for Gravograph .CHR engraving fonts, plus UI to
convert placed text into engraved geometry in the CAD converter.
The .CHR files are obfuscated with a single-byte XOR. Different
GravoStyle releases use different keys (0x2F in older versions, 0xCF in
the 7000 series, and others across the font library), so the key is
auto-detected from byte 1 of the file: the font name is ASCII stored as
UTF-16LE, so the high byte of its first character is 0x00 in plaintext
and the raw byte equals the key. This reads every font in a GravoStyle
install regardless of version, not just one hardcoded key.
UI: right-clicking a text item in EntityView raises TextConvertRequested;
CadConverterForm renders it via ChrFont with H/V alignment and adds the
result on an ENGRAVE layer.
Tests use Xunit.SkippableFact and a gitignored test-config.json so the
suite points at a local .CHR file without committing proprietary assets.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
