Oh My Zsh required variables are not set, breaking plugins

[henrebotha]

Attempt to use an Oh My Zsh plugin such as mise, and it will encounter errors due to the absence of variables that Oh My Zsh assumes to exist, such as $ZSH_CACHE_DIR.

zcomet should set these kinds of variables so that e.g. zcomet load ohmyzsh 'plugins/mise' can work correctly.

I think the correct default value is something like "$ZDOTDIR"/.zcomet/repos/ohmyzsh/ohmyzsh/cache.