fix(center): enable CORS for auth preflight and desktop origins

src/main.ts

@@ -28,6 +28,29 @@ async function bootstrap() {
   validateEnv();
 
   const app = await NestFactory.create(AppModule);
+  const corsOrigins = (process.env.FABRIC_BACKEND_CENTER_CORS_ORIGINS ?? '')
+    .split(',')
+    .map((x) => x.trim())
+    .filter(Boolean);
+
+  app.enableCors({
+    origin: (origin, callback) => {
+      // no Origin header: curl/server-to-server/most desktop local calls
+      if (!origin) return callback(null, true);
+
+      // desktop/electron local file origin
+      if (origin === 'null') return callback(null, true);
+
+      // empty allowlist => allow all origins
+      if (!corsOrigins.length) return callback(null, true);
+
+      if (corsOrigins.includes(origin)) return callback(null, true);
+      return callback(new Error('CORS origin not allowed'), false);
+    },
+    methods: ['GET', 'POST', 'PATCH', 'PUT', 'DELETE', 'OPTIONS'],
+    allowedHeaders: ['Content-Type', 'Authorization', 'x-client-name', 'x-request-id', 'x-api-key'],
+    credentials: false,
+  });
   app.setGlobalPrefix('api');
   const metrics = app.get(MetricsService);
   app.use(createRequestContextMiddleware('center', metrics));