Macro impl_capability_variant 

macro_rules! impl_capability_variant {
    ( $($ty:ty),+ $(,)? ) => { ... };
}

Blanket‑implement CapabilityVariant for every leaf enum that

• derives EnumIter (from strum_macros) and
• provides intrinsic_dimension_ratings().

The OnceLock caches avoid recomputing vectors on every call, while EnumIter eliminates any need for unstable variant_count or unsafe transmutes.