已知椭圆\(C_{1}{:}\dfrac{x^{2}}{a^{2}}{+}\dfrac{y^{2}}{b^{2}}{=}1(a{ > }b{ > }0)\)的右顶点与抛物线\(C_{2}{:}y^{2}{=}2px(p{ > }0)\)的焦点重合,椭圆\(C_{1}\)的离心率为\(\dfrac{1}{2}\),过椭圆\(C_{1}\)的右焦点\(F\)且垂直于\(x\)轴的直线截抛物线所得的弦长为\(4\sqrt{2}\).
\((1)\)求椭圆\(C_{1}\)和抛物线\(C_{2}\)的方程;
\((2)\)过点\(A({-}2{,}0)\)的直线\(l\)与\(C_{2}\)交于\(M{,}N\)两点,点\(M\)关于\(x\)轴的对称点为
,证明:直线
恒过一定点.