Improve bootstrap robustness and add safety checks

- Fix /tmp/yay conflict with rm -rf before clone
- Use script directory instead of current directory
- Add pipefail to error handling
- Add command existence checks for mise/zoxide in .zshrc
- Add HTTPS clone option in README

arch-config/files/home/.zshrc

@@ -5,10 +5,14 @@ plugins=(git zsh-autosuggestions zsh-syntax-highlighting)
 source $ZSH/oh-my-zsh.sh
 
 # mise
-eval "$(mise activate zsh)"
+if command -v mise &> /dev/null; then
+    eval "$(mise activate zsh)"
+fi
 
 # zoxide
-eval "$(zoxide init zsh)"
+if command -v zoxide &> /dev/null; then
+    eval "$(zoxide init zsh)"
+fi
 
 # Aliases
 alias ls='ls --color=auto'