feat(oa): switch web-admin OA APIs to initiatorSelectByNode

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

web-admin/src/views/oa-approval/start/index.vue

@@ -282,9 +282,8 @@
     try {
       const preview = await fetchOaFlowPreview(appId, {
         formData: { ...formData.value },
-        initiatorSelectUserIds: needInitiatorSelect.value
-          ? [...initiatorSelectUserIds.value]
-          : undefined
+        // Task 4: API 已切到按节点 map；完整 UI 见 Task 5–6
+        initiatorSelectByNode: {}
       })
       flowResolved.value = preview?.resolved !== false
       flowPendingMessage.value =
@@ -396,9 +395,8 @@
       const data: any = await fetchStartOaInstance({
         appId: picked.value.id,
         formData: { ...formData.value },
-        initiatorSelectUserIds: needInitiatorSelect.value
-          ? [...initiatorSelectUserIds.value]
-          : undefined
+        // Task 4: API 已切到按节点 map；完整 UI 见 Task 5–6
+        initiatorSelectByNode: {}
       })
       dlgVisible.value = false
       if (data?.id) {