Let $m$ and $n$ be real numbers. In the rectangular coordinate plane, a circle passing through point $A(4, 1)$ is drawn with equation
$$x^{2} + y^{2} - 2x + 6y = n$$
The line $y = mx$ drawn in the plane intersects this circle at points $B$ and $C$.
Given that $m(\widehat{BAC}) = 90^{\circ}$, what is the sum $m + n$?
A) 8
B) 9
C) 10
D) 11
E) 12