feat(shell): create cached-eval helper to improve shell startup speed.

zsh/zoxide.zsh

@@ -3,7 +3,7 @@
 #
 
 if command-exists zoxide; then
-  eval "$(zoxide init --cmd zox zsh)"
+  cached-eval "$(command -v zoxide)" zoxide init --cmd zox zsh
 
   # Use functions to allow regular zsh completion for cd to work.
   cd() { __zoxide_z "$@"; }