feat(emacs): Eshell stuff

- Fancify prompt
  - Shows success of last command.
  - TRAMP prefix is made distinct.
  - CWD is abbreviated.
- cd to project root (`cdp`).
- Imitate using `C-d` / send-EOF to exit.
- Opening popup shell puts user in insert state.
- Fixes TRAMP customisation.

Nicely done! }:3

users/crumb/programs/emacs/lib/syd-project.el

@@ -8,5 +8,9 @@
   (when-let* ((project (project-current nil dir)))
     (project-root project)))
 
+(defun syd-cd-project ()
+  "Change the working directory to the root of the current project."
+  (cd (syd-project-root)))
+
 (provide 'syd-project)
 ;;; syd-project.el ends here