Merge pull request #423 from NuschtOS/fix-remote-build

nix: fix remote build user by configuring usable shell

Author: SuperSandro2000

modules/nix.nix

@@ -80,6 +80,10 @@ in
     users.users.${cfg.remoteBuilder.name} = lib.mkIf cfg.remoteBuilder.enable {
       group = "nogroup";
       isSystemUser = true;
+      # sshd runs the forced command from authorizedKeys as `$shell -c ...`,
+      # so a nologin shell (the default for system users) breaks remote building with:
+      # "protocol mismatch, got 'This account is currently not available.'"
+      shell = pkgs.bashInteractive;
       openssh.authorizedKeys.keys = map
         (key:
           let