nixos/n8n: improve environment type

nixos/modules/services/misc/n8n.nix

@@ -34,7 +34,13 @@ in
         See <https://docs.n8n.io/hosting/configuration/environment-variables/> for available options.
       '';
       type = lib.types.submodule {
-        freeformType = with lib.types; attrsOf str;
+        freeformType =
+          with lib.types;
+          attrsOf (oneOf [
+            str
+            (coercedTo int toString str)
+            (coercedTo bool builtins.toJSON str)
+          ]);
         options = {
           GENERIC_TIMEZONE = lib.mkOption {
             type = with lib.types; nullOr str;

nixos/tests/n8n.nix

@@ -14,7 +14,11 @@ in
     {
       services.n8n = {
         enable = true;
-        environment.WEBHOOK_URL = webhookUrl;
+        environment = {
+          WEBHOOK_URL = webhookUrl;
+          N8N_TEMPLATES_ENABLED = false;
+          DB_PING_INTERVAL_SECONDS = 2;
+        };
       };
     };
 
@@ -26,5 +30,7 @@ in
     machine.succeed("grep -qF 'HOME=/var/lib/n8n' /etc/systemd/system/n8n.service")
     machine.fail("grep -qF 'GENERIC_TIMEZONE=' /etc/systemd/system/n8n.service")
     machine.succeed("grep -qF 'N8N_DIAGNOSTICS_ENABLED=false' /etc/systemd/system/n8n.service")
+    machine.succeed("grep -qF 'N8N_TEMPLATES_ENABLED=false' /etc/systemd/system/n8n.service")
+    machine.succeed("grep -qF 'DB_PING_INTERVAL_SECONDS=2' /etc/systemd/system/n8n.service")
   '';
 }