chore(backlog): 记录 g20 完成

.ua/backlog.json

@@ -522,7 +522,7 @@
       "title": "inputNumber 长按连发步进",
       "motivation": "大步长调节时反复点按钮太累，主流数字输入都支持长按持续步进",
       "acceptance": "按住 −/+ 按钮 400ms 后每 100ms 连续步进，松开或移出即停；单击行为不变；npm run check 全绿",
-      "status": "open",
+      "status": "done",
       "notes": "自补：既有组件可用性细节"
     }
   ]

.ua/iterations.log

@@ -64,3 +64,4 @@
 {"ts":"2026-10-26T11:00:20+08:00","id":"g17","result":"done","commit":"27d797a","summary":"select 展开后键入字母按前缀环形快跳选项，1s 无输入重置缓冲，既有键盘导航不变"}
 {"ts":"2026-10-26T11:04:02+08:00","id":"g18","result":"done","commit":"44b8697","summary":"textField clearable 开启后有值即显一键清空按钮，点击同步信号与 onInput，空值自动隐藏"}
 {"ts":"2026-10-26T11:06:38+08:00","id":"g19","result":"done","commit":"34abe3f","summary":"textarea maxCount 设原生 maxlength 并在下方附加块显示实时 n/limit 计数"}
+{"ts":"2026-10-26T11:08:38+08:00","id":"g20","result":"done","commit":"646fed9","summary":"inputNumber 长按 −/+ 400ms 后每 100ms 连发步进，松开或移出即停，单击不变"}