Add Emacs desktop provisioning and dev toolchain packages

Install Emacs and copy the desktop .emacs.d config so the editor setup is managed with the rest of desktop dotfiles. Add vterm/build/debug dependencies plus C/C++ and Go tooling needed by the configured workflow.

dotfiles/desktop/.emacs.d/lisp/lang/shell.el

@@ -0,0 +1,11 @@
+(with-eval-after-load 'flycheck
+  (add-hook 'bash-ts-mode-hook 'flycheck-mode))
+
+(use-package reformatter
+  :ensure t
+  :config
+  (reformatter-define shfmt-format
+    :program "shfmt"
+    :args '("-i" "2" "-ci")))
+
+(add-hook 'bash-ts-mode-hook #'shfmt-format-on-save-mode)