panel service: set NIX_BIN

panel/default.nix

@@ -8,7 +8,6 @@
   },
 }:
 let
-  inherit (pkgs) lib;
   manage = pkgs.writeScriptBin "manage" ''
     exec ${pkgs.lib.getExe pkgs.python3} ${toString ./src/manage.py} $@
   '';
@@ -23,8 +22,6 @@ in
     env = {
       NPINS_DIRECTORY = toString ../npins;
       # explicitly use nix, as e.g. lix does not have configurable-impure-env
-      NIX_BIN = lib.getExe pkgs.nix;
-      REPO_DIR = toString ../.;
       CREDENTIALS_DIRECTORY = builtins.toString ./.credentials;
       DATABASE_URL = "sqlite:///${toString ./src}/db.sqlite3";
     };

panel/nix/configuration.nix

@@ -193,6 +193,8 @@ in
       environment = {
         USER_SETTINGS_FILE = "${configFile}";
         DATABASE_URL = database-url;
+        NIX_BIN = lib.getExe pkgs.nix;
+        REPO_DIR = ../..;
       };
     };