Let \( A = \begin{pmatrix} \sin \theta & \cos \theta \\ \cos \theta & \sin \theta \end{pmatrix} \) and \( A + A^T - 2I = 0 \), where \( A^T \) is the transpose of \( A \) and \( I \) is the identity matrix. The value of \( \theta \) (in degrees) is ............