feat(lib): add auth-kit

.env.example

@@ -6,6 +6,10 @@ LOG_FILE_NAME=iam.log
 
 DATABASE_URL=postgres://iam_service_user:iam_service_password@localhost:5432/iam_service_db
 JWT_SECRET=please_replace_with_a_secure_random_string
+JWT_KEY_ID=default
+JWT_PRIVATE_KEY_PEM=
+JWT_PUBLIC_KEY_PEM=
+JWT_JWKS_EXTRA_KEYS_JSON=
 PORT=3000
 
 # Optional: Scalar/OpenAPI example injection