test(multiple-subtitles): [PKG-MULTI-SUB-02] reproduce failures and native resource leaks

refactor/tasks.json

@@ -2277,11 +2277,14 @@
         "ENG-03",
         "ENG-05"
       ],
-      "status": "todo",
+      "status": "done",
       "risk": "H",
       "deliverable": "VTT/SRT/ASS、编码/重叠 cue/排序/空轨/失败与切换",
       "acceptance": "旧版本行为可重跑，成功/失败/切源/销毁有必要断言",
-      "evidence": []
+      "evidence": [
+        "baselines/multiple-subtitles-failures.json",
+        "changes/2026-09-13-PKG-MULTI-SUB-02-failures.md"
+      ]
     },
     {
       "id": "PKG-MULTI-SUB-03",