feat(systemd): support configurable service environment variables

test/test.smartdaemon.ts

@@ -54,6 +54,29 @@ tap.test('should generate systemd unit file with User/Group directives', async (
   expect(unitFileContent).toInclude('Group=www-data');
   expect(unitFileContent).toInclude('# user: www-data');
   expect(unitFileContent).toInclude('# group: www-data');
+  expect(unitFileContent).not.toInclude('max_old_space_size=100');
+});
+
+tap.test('should generate systemd unit file with configured environment', async () => {
+  const testService = await smartdaemon.SmartDaemonService.createFromOptions(
+    testSmartdaemon,
+    {
+      name: 'test-service-env',
+      description: 'A test service with environment',
+      command: 'node test.js',
+      workingDir: '/tmp',
+      version: '1.0.0',
+      environment: {
+        NODE_OPTIONS: '--max_old_space_size=1024',
+        CUSTOM_VALUE: 'quoted "value"',
+      },
+    }
+  );
+
+  const unitFileContent = testSmartdaemon.templateManager.generateUnitFileForService(testService);
+
+  expect(unitFileContent).toInclude('Environment="NODE_OPTIONS=--max_old_space_size=1024"');
+  expect(unitFileContent).toInclude('Environment="CUSTOM_VALUE=quoted \\"value\\""');
 });
 
 tap.test('should handle services without user/group', async () => {
@@ -82,4 +105,4 @@ tap.test('should create smartdaemon with sudo password option', async () => {
   expect(daemonWithPassword.systemdManager.sudoPassword).toEqual('test-password');
 });
 
-export default tap.start();
+export default tap.start();