app: pass through $SHELL

Signed-off-by: Ophestra <cat@gensokyo.uk>

nixos.nix

@@ -88,10 +88,14 @@ in
 
                   conf = {
                     inherit (app) id;
-                    path = if app.path == null then pkgs.writeScript "${app.name}-start" ''
+                    path =
+                      if app.path == null then
+                        pkgs.writeScript "${app.name}-start" ''
                           #!${pkgs.zsh}${pkgs.zsh.shellPath}
                           ${script}
-                    '' else app.path;
+                        ''
+                      else
+                        app.path;
                     args = if app.args == null then [ "${app.name}-start" ] else app.args;
 
                     confinement = {