tensor_order's primary template is now left undefined: a partial specialization detects the order
structurally for a type that exposes exactly one indexing shape, while a type exposing both (an
N x 1 matrix modeling a vector, as Eigen does) is ambiguous, has no default, and must be specialized
by an adapter or an ordinary template<>. numeric_field consults tensor_order to reach a scalar
element rather than a structural guess, and is defined only where the order is, so an ambiguous
unspecialized type is rejected on both axes (SFINAE-friendly, closing the cross-TU ODR hazard of
guessing). A shared detail::specified concept replaces the open-coded undefined_t checks in
frame_projection and quantity_point bounds.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Mateusz Pusz
8a505080b5