GAIC Math 2024 Problem 88

In tetrahedron $ABCD$, triangle $ABC$ is an equilateral triangle, $\angle BCD=90^{\circ}$, $BC=CD=1$,$AC=\sqrt{3}$,$E$ and $F$ are the midpoints of edges $BD$ and $AC$ respectively. Then the cosine of the angle formed by lines $AE$ and $BF$ is _____.