Switch to emacs-wayland on Arch, use package-provided emacs.service

- emacs → emacs-wayland in arch_profile_packages
- Remove custom emacs.service deployment: replace full .config/systemd/user/
  directory copy with individual service files (rclone-pcloud, syncthing)
- Remove emacs.service from desktop_systemd_user_services
- Enable package-provided /usr/lib/systemd/user/emacs.service via symlink
  in profile_desktop_gnome

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ansible/inventory/group_vars/desktop.yml

@@ -117,10 +117,14 @@ desktop_common_dotfiles:
     mode: "0600"
 
 desktop_arch_dotfiles:
-  - name: systemd user services
-    src: .config/systemd/user/
-    dest: .config/systemd/user/
-    mode: preserve
+  - name: rclone pcloud systemd user service
+    src: .config/systemd/user/rclone-pcloud.service
+    dest: .config/systemd/user/rclone-pcloud.service
+    mode: "0644"
+  - name: syncthing systemd user service
+    src: .config/systemd/user/syncthing.service
+    dest: .config/systemd/user/syncthing.service
+    mode: "0644"
   - name: MIME application defaults
     src: .config/mimeapps.arch.list
     dest: .config/mimeapps.list