perf(core): [MOD-03] avoid redundant slider attribute writes

refactor/tasks.json

@@ -4537,11 +4537,14 @@
         "CORE-22",
         "ENG-08"
       ],
-      "status": "todo",
+      "status": "doing",
       "risk": "M",
       "deliverable": "DOM 读写、进度更新、持久化、初始化的测量与改进",
       "acceptance": "相同设备媒体多次比较，契约不变，收益及无效尝试记录；复用 BASE-06 的原始样本与测量限制，至少三组同环境旧新配对，不以单次变快宣称收益",
-      "evidence": []
+      "evidence": [
+        "changes/2026-09-14-MOD-03-slider-updates.md",
+        "baselines/slider-updates-validation.json"
+      ]
     },
     {
       "id": "MOD-04",