docs(#414): add TRUSTED_ORIGINS and COOKIE_DOMAIN to .env.example

Refs #414

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/main.ts

@@ -2,6 +2,7 @@ import { NestFactory } from "@nestjs/core";
 import { ValidationPipe } from "@nestjs/common";
 import cookieParser from "cookie-parser";
 import { AppModule } from "./app.module";
+import { getTrustedOrigins } from "./auth/auth.config";
 import { GlobalExceptionFilter } from "./filters/global-exception.filter";
 
 function getPort(): number {
@@ -47,39 +48,9 @@ async function bootstrap() {
   app.useGlobalFilters(new GlobalExceptionFilter());
 
   // Configure CORS for cookie-based authentication
-  // SECURITY: Cannot use wildcard (*) with credentials: true
-  const isDevelopment = process.env.NODE_ENV !== "production";
-
-  const allowedOrigins = [
-    process.env.NEXT_PUBLIC_APP_URL ?? "http://localhost:3000",
-    "https://app.mosaicstack.dev", // Production web
-    "https://api.mosaicstack.dev", // Production API
-  ];
-
-  // Development-only origins (not allowed in production)
-  if (isDevelopment) {
-    allowedOrigins.push("http://localhost:3001"); // API origin (dev)
-  }
-
+  // Origin list is shared with BetterAuth trustedOrigins via getTrustedOrigins()
   app.enableCors({
-    origin: (
-      origin: string | undefined,
-      callback: (err: Error | null, allow?: boolean) => void
-    ): void => {
-      // Allow requests with no Origin header (health checks, server-to-server,
-      // load balancer probes). These are not cross-origin requests per the CORS spec.
-      if (!origin) {
-        callback(null, true);
-        return;
-      }
-
-      // Check if origin is in allowed list
-      if (allowedOrigins.includes(origin)) {
-        callback(null, true);
-      } else {
-        callback(new Error(`Origin ${origin} not allowed by CORS`));
-      }
-    },
+    origin: getTrustedOrigins(),
     credentials: true, // Required for cookie-based authentication
     methods: ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"],
     allowedHeaders: ["Content-Type", "Authorization", "Cookie", "X-CSRF-Token", "X-Workspace-Id"],