Resolve font specification to actual font path or name
Supports: PDF standard fonts, absolute paths, https URLs on public hosts, 'auto' detection
Returns null if font cannot be resolved (caller should use fallback)
Throws if a URL is refused or its download fails
Resolve font specification to actual font path or name Supports: PDF standard fonts, absolute paths, https URLs on public hosts, 'auto' detection Returns null if font cannot be resolved (caller should use fallback) Throws if a URL is refused or its download fails