Function style_spec_from_wit 

pub fn style_spec_from_wit(spec: StyleSpec) -> StyleSpec

Convert a WIT style-spec to the native StyleSpec.

Total — every WIT shape maps, so there is no failure mode here and the register-element err is reserved for registry-level rejections. family and weight have no WIT counterpart by design (see theme.wit), so they stay None; a plugin cannot set them, which is the intended surface rather than a lossy conversion.