test(thumbnail): [PKG-TOOL-THUMB-02] reproduce extraction and resource lifecycle gaps

refactor/tasks.json

@@ -3765,11 +3765,14 @@
         "ENG-03",
         "ENG-05"
       ],
-      "status": "todo",
+      "status": "done",
       "risk": "H",
       "deliverable": "文件输入/拖放、抽帧网格、begin/end、进度/失败/重复任务",
       "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/thumbnail-behavior-validation.json",
+        "changes/2026-09-13-PKG-TOOL-THUMB-02-behavior.md"
+      ]
     },
     {
       "id": "PKG-TOOL-THUMB-03",