feat(oa): add leave kit with auto duration calculation

Co-authored-by: Cursor <cursoragent@cursor.com>

web-admin/src/components/oa-approval/OaLeaveKit.vue

@@ -0,0 +1,29 @@
+<!-- 请假套件：仅组合容器，不改变子字段标准展示样式；工时在 props -->
+<template>
+  <div class="oa-leave-kit" v-bind="$attrs">
+    <slot />
+  </div>
+</template>
+
+<script setup lang="ts">
+  defineOptions({ name: 'OaLeaveKit', inheritAttrs: false })
+
+  /** 工时属性由 FormCreate 写入 props，供 schema / 运行时读取，本组件不展示 */
+  defineProps<{
+    morningStart?: string
+    morningEnd?: string
+    afternoonStart?: string
+    afternoonEnd?: string
+    startField?: string
+    endField?: string
+    durationField?: string
+    typeField?: string
+  }>()
+</script>
+
+<style scoped lang="scss">
+  /* 无边框/底色/标题：子字段视觉与标准组件一致 */
+  .oa-leave-kit {
+    width: 100%;
+  }
+</style>