fix: align auth-disabled mode and mock history loading (#3471)

* fix: align auth-disabled mode and mock history loading

* fix: address auth-disabled review feedback

* test: cover auth-disabled backend contract

* style: format frontend tests

* fix: address follow-up review comments

frontend/src/core/auth/auth-disabled-user.ts

@@ -0,0 +1,23 @@
+import type { User } from "./types";
+
+export const AUTH_DISABLED_USER: User = {
+  id: "e2e-user",
+  email: "e2e@test.local",
+  system_role: "admin",
+  needs_setup: false,
+};
+
+const PRODUCTION_ENV_VALUES = new Set(["prod", "production"]);
+
+function isExplicitProductionEnvironment() {
+  return ["DEER_FLOW_ENV", "ENVIRONMENT"].some((name) =>
+    PRODUCTION_ENV_VALUES.has((process.env[name] ?? "").trim().toLowerCase()),
+  );
+}
+
+export function isAuthDisabledMode() {
+  return (
+    process.env.DEER_FLOW_AUTH_DISABLED === "1" &&
+    !isExplicitProductionEnvironment()
+  );
+}