chore: clean up home configuration and simplify arty.yml

- Add Rust cargo environment to .zshenv
- Make oh-my-zsh sourcing conditional in .zshrc for safer initialization
- Simplify arty.yml: remove env-specific repository references, clean formatting
- Remove unused .vscode/settings.json

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.zshrc

@@ -154,7 +154,7 @@ ZSH_THEME="powerlevel10k/powerlevel10k"
 # Add wisely, as too many plugins slow down shell startup.
 plugins=(git pm2 gh sudo ssh ruby rust python node github rsync nvm rbenv pyenv docker docker-compose qrcode zsh-autosuggestions zsh-syntax-highlighting zsh-interactive-cd zsh-navigation-tools)
 
-source $ZSH/oh-my-zsh.sh
+[[ ! -f $ZSH/oh-my-zsh.sh ]] || source $ZSH/oh-my-zsh.sh
 
 # User configuration