test(matrix): use preferred temp root

extensions/matrix/test-support.ts

@@ -1,7 +1,7 @@
 // Matrix test support owns plugin-local fixture cleanup.
 import fs from "node:fs";
-import os from "node:os";
 import path from "node:path";
+import { resolvePreferredOpenClawTmpDir } from "openclaw/plugin-sdk/temp-path";
 
 type RegisterTempDirCleanup = (cleanup: () => void) => unknown;
 
@@ -16,7 +16,7 @@ export function useAutoCleanupTempDirTracker(registerCleanup: RegisterTempDirCle
   return {
     make(prefix: string): string {
       // openclaw-temp-dir: allow extension-local test support cannot import the core-only tracker.
-      const dir = fs.mkdtempSync(path.join(os.tmpdir(), prefix));
+      const dir = fs.mkdtempSync(path.join(resolvePreferredOpenClawTmpDir(), prefix));
       dirs.add(dir);
       return dir;
     },