fix: initialize configured auth in production builds

packages/auth/src/engine.ts

@@ -11,6 +11,7 @@ import {
 import { inferIdentityType, normalizeIdentity, publicUser } from "./normalize.ts";
 import { assertPasskeyProvider, MemoryPasskeyChallengeStore } from "./passkeys/index.ts";
 import { evaluateAuthRisk } from "./risk.ts";
+import { setDefaultAuthEngine } from "./runtime.ts";
 import type { AuthStore } from "./store.ts";
 import { generateTotpSecret, totpUri, verifyTotp } from "./totp/index.ts";
 import type {
@@ -2298,5 +2299,9 @@ export function createAuthEngine(options: AuthEngineOptions): AuthEngine {
     },
   };
 
+  // The application config is evaluated in both dev and generated production
+  // runtimes. Registering here makes that configured engine available to the
+  // package-owned routes without an application startup shim.
+  setDefaultAuthEngine(engine);
   return engine;
 }