If the area of the region \( \{(x,y): -1 \le x \le 1,\, 0 \le y \le a + e^{|x|} - e^{-x},\, a > 0\} \) is \( \frac{e^2 + 8e + 1}{e} \), then the value of \( a \) is:
\( 6 \)
\( 7 \)
\( 5 \)
\( 8 \)