Function render_html_reflow_ttf_with 

pub fn render_html_reflow_ttf_with(
    source: Option<&[VertBox]>,
    geometry: &PageGeometry,
    store: &TtfFontStore,
    images: &[ImageResource],
    extras: &DocExtras,
    links: &[(DecoId, AnnotAction)],
    dests: &[(DecoId, String)],
) -> Result<String, HtmlError>

Same as render_html_reflow, but rendering under a real TtfFontStore — every inline run’s <span> gets an explicit font-family naming the @font-face this function’s <style> block embeds for every physical font file actually referenced, exactly crate::render_html_fixed_ttf_with’s Slice-3 fidelity mitigation.