fix: 修复审批功能和数据加载问题

- BusinessTripService 添加 ApprovalNode use 语句
- 修复 approve 方法中的字段引用错误（flow_id 替代 order_id）
- 修复 approve 方法中的类型引用错误（type 替代 node_type）
- getList 方法添加 approvalOrder 关联加载
- 完善审批逻辑：检查用户是否在当前节点审批人列表中
- 前后端联调测试通过

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/service/BusinessTripService.php

@@ -6,6 +6,7 @@ use app\model\BusinessTrip;
 use app\model\BusinessTripItinerary;
 use app\model\ApprovalOrder;
 use app\model\ApprovalFlow;
+use app\model\ApprovalNode;
 use app\model\ApprovalRecord;
 use app\model\User;
 use support\Db;
@@ -160,7 +161,7 @@ class BusinessTripService
      */
     public function getList(int $userId, string $type = 'my', int $page = 1, int $pageSize = 20): array
     {
-        $query = BusinessTrip::with(['user', 'itineraries']);
+        $query = BusinessTrip::with(['user', 'itineraries', 'approvalOrder']);
 
         switch ($type) {
             case 'my':
@@ -397,7 +398,7 @@ class BusinessTripService
             $isApprover = false;
 
             foreach ($currentNodes as $nodeId) {
-                $node = ApprovalNode::where('order_id', $approvalOrder->id)
+                $node = ApprovalNode::where('flow_id', $approvalOrder->flow_id)
                     ->where('id', $nodeId)
                     ->first();
 
@@ -405,13 +406,11 @@ class BusinessTripService
                     continue;
                 }
 
-                // 检查是否是单人审批节点
-                if ($node->node_type === 'single_approve') {
-                    $approvers = $node->approvers ?? [];
-                    if (in_array($userId, $approvers)) {
-                        $isApprover = true;
-                        break;
-                    }
+                // 检查用户是否在审批人列表中
+                $approvers = $node->approvers ?? [];
+                if (in_array($userId, $approvers)) {
+                    $isApprover = true;
+                    break;
                 }
             }
 
@@ -433,7 +432,7 @@ class BusinessTripService
             ApprovalRecord::create([
                 'order_id' => $approvalOrder->id,
                 'node_id' => $currentNodes[0] ?? 1,
-                'node_type' => 'single_approve',
+                'node_type' => 'approver',
                 'approver_id' => $userId,
                 'action' => $action,
                 'comment' => $comment,