test(utils): share temp-dir helper across cli and web tests

src/test-utils/temp-dir.ts

@@ -0,0 +1,12 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+
+export async function withTempDir<T>(prefix: string, run: (dir: string) => Promise<T>): Promise<T> {
+  const dir = await fs.mkdtemp(path.join(os.tmpdir(), prefix));
+  try {
+    return await run(dir);
+  } finally {
+    await fs.rm(dir, { recursive: true, force: true });
+  }
+}