nixos/soju: add sojuctl wrapper with config path

The config is a in an arbitrary nix store path, and is necessary to
invoke sojuctl. Without the wrapper, you have to read the systemd unit
or use a similar trick to find it.

nixos/doc/manual/release-notes/rl-2405.section.md

@@ -485,7 +485,7 @@ The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been m
 
 - The `krb5` module has been rewritten and moved to `security.krb5`, moving all options but `security.krb5.enable` and `security.krb5.package` into `security.krb5.settings`.
 
-- `services.soju` now has the option `adminSocket.enable`. This option defaults to `true`, and creates a unix admin socket at `/run/soju/admin`.
+- `services.soju` now has a wrapper for the `sojuctl` command, pointed at the service config file. It also has the new option `adminSocket.enable`, which creates a unix admin socket at `/run/soju/admin`.
 
 - Gitea 1.21 upgrade has several breaking changes, including:
   - Custom themes and other assets that were previously stored in `custom/public/*` now belong in `custom/public/assets/*`

nixos/modules/services/networking/soju.nix

@@ -25,6 +25,10 @@ let
 
     ${cfg.extraConfig}
   '';
+
+  sojuctl = pkgs.writeShellScriptBin "sojuctl" ''
+    exec ${cfg.package}/bin/sojuctl --config ${configFile} "$@"
+  '';
 in
 {
   ###### interface
@@ -120,6 +124,8 @@ in
       }
     ];
 
+    environment.systemPackages = [ sojuctl ];
+
     systemd.services.soju = {
       description = "soju IRC bouncer";
       wantedBy = [ "multi-user.target" ];