ut3_norm_orthogonalized
=======================

.. py:function:: t3toolbox.backend.ut3_linalg.ut3_norm_orthogonalized(x)

   .. code-block:: python

      def ut3_norm_orthogonalized(x: UT3Data) -> NDArray:  # HS norm, shape=stack_shape


   Hilbert-Schmidt norm of an already-left-orthogonalized uniform T3 (the frontend left-orthogonalizes
   first): masks + squashes, then the norm is the Frobenius norm of the last TT core (all others are
   orthonormal). Mirrors the ragged ``t3_norm`` fast path.