feat(core-api): compose @repo/auth/api into appRouter under 'auth' namespace

packages/auth/src/index.ts

@@ -1,6 +1,7 @@
 export type { User } from "./entities/user";
 export type { Session } from "./entities/session";
 export type { Cookie } from "./entities/cookie";
+export type { AuthRouter } from "./integrations/api/router";
 export {
   AuthenticationError,
   UnauthenticatedError,