normalizeFontFamily function
Normalizes a font family name, mapping generic/legacy families to our bundled default.
Implementation
String normalizeFontFamily(String? fontFamily) {
if (fontFamily == null || fontFamily.isEmpty) return 'DejaVu Sans';
final lower = fontFamily.toLowerCase();
if (lower == 'sans-serif' || lower == 'arial' || lower == 'helvetica') {
return 'DejaVu Sans';
}
return fontFamily;
}