Remove tmux-workspaces in favor of tmuxinator-only workflow

- Delete tmux-workspaces.zsh and .tmux-templates directory
- Remove TW_* config settings from dotfiles.conf
- Clean up tmuxinator.zsh (remove import/integration code)
- Update README, INSTALL, and REFERENCE docs
- Fix editor config: .zshrc now uses DEFAULT_EDITOR from dotfiles.conf

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

zsh/.zshrc

@@ -254,6 +254,8 @@ _dotfiles_dir="$HOME/.dotfiles"
 # Load dotfiles.conf first (sets DOTFILES_DIR and other vars)
 if [[ -f "$_dotfiles_dir/dotfiles.conf" ]]; then
     source "$_dotfiles_dir/dotfiles.conf"
+    # Apply DEFAULT_EDITOR from config if set
+    [[ -n "$DEFAULT_EDITOR" ]] && export EDITOR="$DEFAULT_EDITOR" VISUAL="$DEFAULT_EDITOR"
 else
     DOTFILES_DIR="$HOME/.dotfiles"
     DOTFILES_BRANCH="main"