Attribute Macro cap 

#[cap]

Unified capability attribute macro.

On Trait: Register trait for caps system

#[cap]
trait Serializable {
    fn serialize(&self) -> Vec<u8>;
}
// Generates: IsSerializable marker, is_serializable::<T>() function
// Now usable in specialize! without #[map]

On Struct/Enum: Auto-detect standard traits

#[cap]
struct MyType { data: String }
// Enables trait detection via caps system

DEPRECATED: Use #[derive(AutoCaps)] for types and #[trait_autocaps] for traits.