shells: get rid of direnv, work around dynamic vars with simple scripts

dot_config/fish/config.fish

@@ -20,10 +20,6 @@ if status is-interactive
         end
     end
 
-    if command -q direnv
-        direnv hook fish | source
-    end
-
     if command -q mise
         mise activate fish | source
     end

dot_config/zsh/settings.zsh

@@ -44,10 +44,6 @@ zstyle ':completion:*:default' list-colors ${(s.:.)LS_COLORS}
 
 unalias ld ls ll &>/dev/null
 
-if testbin direnv; then
-    eval "$(direnv hook zsh)"
-fi
-
 if testbin mise; then
     eval "$(mise activate zsh)"
 fi