fix: wait for arr service to be ready for download clients (#128)

* fix: wait for arr service to be ready before configuring download clients

The downloadclients oneshot service only depended on the config service,
not the arr service itself. Since arr services use Type=simple, systemd
considers them active as soon as the process starts — before they are
actually listening on their port. This caused the downloadclients service
to fail at boot with connection refused errors.

Add the arr service to After/Requires and add an ExecStartPre readiness
check using curl --retry-connrefused to wait until the API is accepting
connections before proceeding.

* fix formatting

---------

Co-authored-by: Kiri Carlson <kiri@walawren.com>

Author: takac

modules/downloadarr/service.nix

@@ -66,13 +66,24 @@ let
     {
       "${serviceName}-downloadclients" = {
         description = "Configure ${serviceName} download clients via API";
-        after = [ "${serviceName}-config.service" ] ++ clientDependencies;
-        requires = [ "${serviceName}-config.service" ] ++ clientDependencies;
+        after = [
+          "${serviceName}.service"
+          "${serviceName}-config.service"
+        ]
+        ++ clientDependencies;
+        requires = [
+          "${serviceName}.service"
+          "${serviceName}-config.service"
+        ]
+        ++ clientDependencies;
         wantedBy = [ "multi-user.target" ];
 
         serviceConfig = {
           Type = "oneshot";
           RemainAfterExit = true;
+          ExecStartPre =
+            "${pkgs.curl}/bin/curl --retry 30 --retry-delay 2 --retry-connrefused -so /dev/null"
+            + " http://127.0.0.1:${builtins.toString serviceConfig.hostConfig.port}${serviceConfig.hostConfig.urlBase}/api/${serviceConfig.apiVersion}/system/status";
         };
 
         script = ''