Improve homebrew + typewritten theme handling in zsh config

zsh/.zprofile

@@ -1,3 +1,6 @@
+if [[ -f "/opt/homebrew/bin/brew" ]]; then
+    eval "$(/opt/homebrew/bin/brew shellenv)"
+fi
 ulimit -n 10240
 export PATH="$PATH:/Users/jdormit/.local/bin"
 eval "$(pyenv init --path)"

zsh/.zshrc

@@ -4,7 +4,15 @@
 # Path to your oh-my-zsh installation.
 export ZSH="$HOME/.oh-my-zsh"
 
-ZSH_THEME="typewritten"
+fpath=($fpath "$HOME/.zfunctions")
+if [ -e "$HOME/.zfunctions/prompt_typewritten_setup" ]; then
+    export ZSH_THEME=""
+    # Set typewritten ZSH as a prompt
+    autoload -U promptinit; promptinit
+    prompt typewritten
+else
+    export ZSH_THEME="robbyrussell"
+fi
 
 # Set list of themes to pick from when loading at random
 # Setting this variable when ZSH_THEME=random will cause zsh to load