GradedSpace ⊕/supremum bypass unit-homogeneity check #538

⊕ and supremum for GradedSpace call the raw 2-arg inner constructor, skipping _check_unit_homogeneity. For GenericUnit sectors this can construct a space violating the documented single-color invariant (the public constructor rejects the same result).

src/spaces/gradedspace.jl:162-173 (⊕), :247-257 (supremum).