chore(backlog): 记录 g113 完成

.ua/backlog.json

@@ -1267,7 +1267,7 @@
       "motivation": "底部操作条（保存 / 取消 / 合计金额）是长表单与详情页的刚需，affix 只会贴顶：调用方得自己监听滚动改 position，或者干脆让操作条跟着内容滚走，用户翻到表单底部才发现按钮在屏幕外",
       "acceptance": "AffixProps 新增 position（top 缺省 / bottom）：贴底时占位容器底边越过「视口底 - offset」才固定，内联边距写 bottom 并清空 top，取消固定时两边都还原；贴顶行为不变；文档参数表 / 手把手 / api 说明同步；npm run check 全绿",
       "notes": "自补：组件可用性；只在 sync 里加一条判定与一个样式分支",
-      "status": "open"
+      "status": "done"
     }
   ]
 }

.ua/iterations.log

@@ -157,3 +157,4 @@
 {"ts":"2026-10-26T14:03:25+08:00","id":"g110","result":"done","commit":"e042143","summary":"select 新增 clearable：有值显 ×（Delete/Backspace 亦可清），复位到未选态"}
 {"ts":"2026-10-26T14:04:44+08:00","id":"g111","result":"done","commit":"f40ef6d","summary":"breadcrumb 新增 maxItems：首项+「…」+末几项，点开完整展开，末项恒为当前页"}
 {"ts":"2026-10-26T14:05:44+08:00","id":"g112","result":"done","commit":"5372fdd","summary":"toast 新增 actionLabel/onAction：撤销按钮点后先收起再回调"}
+{"ts":"2026-10-26T14:06:40+08:00","id":"g113","result":"done","commit":"ec7aaf0","summary":"affix 新增 position=bottom：占位底边越线才贴底固定，边距改 bottom"}