fix(oa): skip dept tree fetch inside form designer iframe

oa-fc-host has no Pinia/auth; mounting OaDeptSelect previously called
fetchDeptTree and surfaced false network errors when dragging the control.

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

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

@@ -1,7 +1,15 @@
 <!-- FormCreate 自定义控件：部门选择（Fresh Mint · PC 树选 + 窄屏抽屉） -->
 <template>
   <div class="oa-dept-select">
-    <template v-if="disabled">
+    <!-- 设计器 iframe 无 Pinia/鉴权，仅展示占位，避免拖入时打接口报错 -->
+    <template v-if="isDesignerHost">
+      <div class="oa-dept-select__preview">
+        <span class="oa-dept-select__placeholder">请选择部门</span>
+        <span class="oa-dept-select__chev">▾</span>
+      </div>
+    </template>
+
+    <template v-else-if="disabled">
       <span class="oa-dept-select__readonly">{{ displayText || '—' }}</span>
     </template>
 
@@ -109,6 +117,17 @@
 
   type TreeNode = { value: string; label: string; children?: TreeNode[] }
 
+  /** 表单设计器隔离宿主（无 Pinia / Token，禁止打业务 API） */
+  function detectDesignerHost() {
+    try {
+      return /oa-fc-host\.html/i.test(String(window.location?.pathname || ''))
+    } catch {
+      return false
+    }
+  }
+
+  const isDesignerHost = detectDesignerHost()
+
   const pathMap = ref(new Map<string, string>())
   const treeSelectData = ref<TreeNode[]>([])
   const isNarrow = ref(false)
@@ -227,6 +246,7 @@
   })
 
   async function loadTree() {
+    if (isDesignerHost) return
     try {
       const tree = (await fetchDeptTree()) || []
       pathMap.value = buildPathLabelMapFromTreeRoots(tree, { nameKey: 'deptName' })
@@ -259,13 +279,7 @@
     width: 100%;
   }
 
-  .oa-dept-select__readonly {
-    color: var(--mint-text, #0f172a);
-    font-size: 14px;
-    line-height: 1.5;
-    word-break: break-all;
-  }
-
+  .oa-dept-select__preview,
   .oa-dept-select__trigger {
     display: flex;
     align-items: center;
@@ -277,9 +291,19 @@
     border-radius: 8px;
     background: #fff;
     text-align: left;
+  }
+
+  .oa-dept-select__trigger {
     cursor: pointer;
   }
 
+  .oa-dept-select__readonly {
+    color: var(--mint-text, #0f172a);
+    font-size: 14px;
+    line-height: 1.5;
+    word-break: break-all;
+  }
+
   .oa-dept-select__placeholder {
     color: var(--mint-text-muted, #94a3b8);
   }