✨ feat(auth): add token expiration configuration option

- modify generateToken method to accept optional expiresIn parameter
- pass expiration configuration to JWTUtil for flexible token lifetime management

src/server/modules/auth/auth.service.ts

@@ -69,8 +69,8 @@ export class AuthService {
     }
   }
 
-  generateToken(user: User): string {
-    return JWTUtil.generateToken(user);
+  generateToken(user: User, expiresIn?: string): string {
+    return JWTUtil.generateToken(user, expiresIn ? { expiresIn } as any : {});
   }
 
   verifyToken(token: string): any {