chore(backlog): 记录 g318 完成

.ua/backlog.json

@@ -3252,7 +3252,7 @@
     {
       "id": "g318",
       "domain": "tooling",
-      "status": "open",
+      "status": "done",
       "title": "配方 20：分步表单向导（步进条 + 按步校验）",
       "motivation": "多步向导是后台最高频的表单形态之一，现有 19 条配方没有覆盖「步进条 + 分步字段 + 步间校验 + 回跳」的组合：stepper 的 active 双向绑定与 formItem 句柄的 validate() 恰好能拼出这个场景，缺一条示范怎么把校验拦在步与步之间，而不是最后一步集体报错。",
       "acceptance": "① recipes.md 新增配方 20（编号连续、含代码块与要点，代码块能被 ua recipes 认出 stepper / formItem / button / card / toast 组件）；② 配方代码与真实签名一致（FormRule.message、button disabled 收 Signal、formItem 句柄 validate）；③ ua recipes 20 与 ua search 均能命中；④ npm run check 通过。",

.ua/iterations.log

@@ -362,3 +362,4 @@
 {"ts":"2026-10-27T00:46:37+08:00","id":"g315","result":"done","commit":"aed5c75","summary":"dataTable 新增 renderDetail：展开列 + 凹陷底详情行，按 rowKey 记展开态，全选框同时归位进 th"}
 {"ts":"2026-10-27T00:47:18+08:00","id":"g316","result":"done","commit":"6c73315","summary":"ua loop 文本与 --json 增 nextId：自补条目前先看清下一个编号，省掉撞号 rebase"}
 {"ts":"2026-10-27T00:55:54+08:00","id":"g317","result":"done","commit":"1a77f76","summary":"全局 ::selection 统一为 accent 30% 淡底（--ua-alpha-line 派生，零新令牌），亮暗主题选区与焦点环同族"}
+{"ts":"2026-10-27T00:59:40+08:00","id":"g318","result":"done","commit":"184406f","summary":"recipes.md 新增配方 20：stepper+formItem 句柄拼分步向导，校验拦在步间、回跳不绕过校验"}