refactor(test): centralize temporary state-dir env setup

src/test-helpers/state-dir-env.ts

@@ -1,3 +1,6 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
 import { captureEnv } from "../test-utils/env.js";
 
 export function snapshotStateDirEnv() {
@@ -12,3 +15,20 @@ export function setStateDirEnv(stateDir: string): void {
   process.env.OPENCLAW_STATE_DIR = stateDir;
   delete process.env.CLAWDBOT_STATE_DIR;
 }
+
+export async function withStateDirEnv<T>(
+  prefix: string,
+  fn: (ctx: { tempRoot: string; stateDir: string }) => Promise<T>,
+): Promise<T> {
+  const snapshot = snapshotStateDirEnv();
+  const tempRoot = await fs.mkdtemp(path.join(os.tmpdir(), prefix));
+  const stateDir = path.join(tempRoot, "state");
+  await fs.mkdir(stateDir, { recursive: true });
+  setStateDirEnv(stateDir);
+  try {
+    return await fn({ tempRoot, stateDir });
+  } finally {
+    restoreStateDirEnv(snapshot);
+    await fs.rm(tempRoot, { recursive: true, force: true });
+  }
+}