Fixes issue #726 by adding config to configToSave object (#728)

The saveConfig() function only includes a hardcoded subset of properties
when writing the config file. Any property not explicitly listed (like
disableResponseStorage) will be dropped.
I have added `disableResponseStorage` to the `configToSave` object as
the immediate fix.

[Linking Issue this fixes.](https://github.com/openai/codex/issues/726)

codex-cli/tests/disableResponseStorage.test.ts

@@ -0,0 +1,43 @@
+/**
+ * codex/codex-cli/tests/disableResponseStorage.test.ts
+ */
+
+import { describe, it, expect, beforeAll, afterAll } from "vitest";
+import { mkdtempSync, rmSync, writeFileSync, mkdirSync } from "node:fs";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+
+import { loadConfig, saveConfig } from "../src/utils/config";
+import type { AppConfig } from "../src/utils/config";
+
+const sandboxHome: string = mkdtempSync(join(tmpdir(), "codex-home-"));
+const codexDir: string = join(sandboxHome, ".codex");
+const yamlPath: string = join(codexDir, "config.yaml");
+
+describe("disableResponseStorage persistence", () => {
+  beforeAll((): void => {
+    // mkdir -p ~/.codex inside the sandbox
+    rmSync(codexDir, { recursive: true, force: true });
+    mkdirSync(codexDir, { recursive: true });
+
+    // seed YAML with ZDR enabled
+    writeFileSync(yamlPath, "model: o4-mini\ndisableResponseStorage: true\n");
+  });
+
+  afterAll((): void => {
+    rmSync(sandboxHome, { recursive: true, force: true });
+  });
+
+  it("keeps disableResponseStorage=true across load/save cycle", async (): Promise<void> => {
+    // 1️⃣ explicitly load the sandbox file
+    const cfg1: AppConfig = loadConfig(yamlPath);
+    expect(cfg1.disableResponseStorage).toBe(true);
+
+    // 2️⃣ save right back to the same file
+    await saveConfig(cfg1, yamlPath);
+
+    // 3️⃣ reload and re-assert
+    const cfg2: AppConfig = loadConfig(yamlPath);
+    expect(cfg2.disableResponseStorage).toBe(true);
+  });
+});