Revert "refactor(nixos): allow grouped SteamCMD arguments"

This reverts commit 46805be6de.

configs/nixos/hosts/pikachu/default.nix

@@ -77,12 +77,18 @@
     arguments = [
       "-nographics"
       "-batchmode"
-      [ "-name" "main" ]
-      [ "-port" "2456" ]
-      [ "-world" "main" ]
-      [ "-savedir" "/pikachu/media/games/servers/valheim/main" ]
-      [ "-password" "foobarbaz" ]
-      [ "-public" "0" ]
+      "-name"
+      "main"
+      "-port"
+      "2456"
+      "-world"
+      "main"
+      "-savedir"
+      "/pikachu/media/games/servers/valheim/main"
+      "-password"
+      "foobarbaz"
+      "-public"
+      "0"
     ];
     udpPorts = [
       2456

configs/nixos/modules/services/steamcmd.nix

@@ -8,7 +8,6 @@ let
   cfg = config.modules.services.steamcmd;
 
   libraryPath = lib.concatStringsSep ":" cfg.libraryDirs;
-  arguments = lib.flatten cfg.arguments;
 
   prepareScript = pkgs.writeShellScript "steamcmd-${cfg.serviceName}-prepare" ''
     set -eu
@@ -38,7 +37,7 @@ let
 
     cd ${lib.escapeShellArg cfg.installDir}
     ${lib.optionalString (cfg.libraryDirs != [ ]) ''export LD_LIBRARY_PATH=${lib.escapeShellArg libraryPath}:''${LD_LIBRARY_PATH-}''}
-    exec ${lib.getExe pkgs.steam-run} ${lib.escapeShellArg cfg.executable} ${lib.escapeShellArgs arguments}
+    exec ${lib.getExe pkgs.steam-run} ${lib.escapeShellArg cfg.executable} ${lib.escapeShellArgs cfg.arguments}
   '';
 
   restartCommand =
@@ -103,15 +102,13 @@ in
     };
 
     arguments = lib.mkOption {
-      type = lib.types.listOf (lib.types.oneOf [
-        lib.types.str
-        (lib.types.listOf lib.types.str)
-      ]);
+      type = lib.types.listOf lib.types.str;
       default = [ ];
       example = [
-        [ "-name" "main" ]
+        "-name"
+        "main"
       ];
-      description = "Arguments passed to the server executable. Nested lists group related arguments and are flattened before execution.";
+      description = "Arguments passed to the server executable.";
     };
 
     libraryDirs = lib.mkOption {