chore(backlog): 记录 g166 完成

.ua/backlog.json

@@ -1684,6 +1684,14 @@
       "acceptance": "stepper 新增 direction：vertical 时圆点成一列、连接线走圆点下方、末步不画线、已完成段用主色；演示页加独立信号的竖向实例；manifest props 表与步骤、llms-full 同步；npm run check 全绿。",
       "notes": "",
       "status": "done"
+    },
+    {
+      "id": "g166",
+      "title": "下拉选项支持分组标题",
+      "motivation": "技术栈 / 部门 / 城市这类长候选集只能平铺，用户得一行行扫；分组要么拆成多个 select，要么在 label 里塞「【前端】Vue」这类假标题。",
+      "acceptance": "OptionItem 与 CheckOption 新增 group：select 在组首插灰色小标题（段间分隔线）、整组过滤无命中时标题隐藏；multiSelect 候选同步支持且小标题不占键盘下标；演示页加分组下拉实例；manifest 的 options 描述与步骤、llms-full 同步；npm run check 全绿。",
+      "notes": "",
+      "status": "done"
     }
   ]
 }

.ua/iterations.log

@@ -210,3 +210,4 @@
 {"ts":"2026-10-26T16:08:23+08:00","id":"g163","result":"done","commit":"6febeba","summary":"verify 补 backlog 编号递增/去重与留痕 ts 时区、单调、未来三类校验"}
 {"ts":"2026-10-26T16:09:59+08:00","id":"g164","result":"done","commit":"b533903","summary":"descriptions 新增 layout=vertical 与 extra 标题插槽"}
 {"ts":"2026-10-26T16:11:06+08:00","id":"g165","result":"done","commit":"804ab3b","summary":"stepper 新增 direction=vertical（圆点下方连线，已走段用主色）"}
+{"ts":"2026-10-26T16:13:05+08:00","id":"g166","result":"done","commit":"a80644c","summary":"select/multiSelect 支持 option.group 分组小标题（过滤后空组标题隐藏）"}