test(subagent-codex): use async rm for real-product temp cleanup

Switch the afterEach cleanup from rmSync to the async rm with 10
retries, matching subagent-claude-code. On native Windows the
synchronous rmSync retry window (5 x 100ms) is too short for the
real Codex subprocess to release its directory handles after exit,
so cleanup repeatedly fails with EPERM; the async variant with a
wider retry window drains the handles before removing the tree.

packages/subagent/subagent-codex/tests/real-product.spec.ts

@@ -4,9 +4,9 @@ import {
   mkdirSync,
   mkdtempSync,
   readFileSync,
-  rmSync,
   writeFileSync,
 } from 'node:fs'
+import { rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { delimiter, join, resolve } from 'node:path'
 import { fileURLToPath } from 'node:url'
@@ -41,7 +41,7 @@ afterEach(async () => {
   await Promise.all(contexts.splice(0).map(ctx => ctx.fiber.dispose()))
   await Promise.all(fixtures.splice(0).map(fixture => fixture.close()))
   for (const root of roots.splice(0)) {
-    rmSync(root, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 })
+    await rm(root, { recursive: true, force: true, maxRetries: 10, retryDelay: 100 })
   }
 })