docs: 整理项目问题文档，修复审批列表数据混乱

- 新增 PROJECT_ISSUES.md 统一管理所有问题和解决方案
- 精简 CLAUDE.md，移除重复的问题记录部分
- 修复审批列表数据混乱问题（React 18 StrictMode + 状态管理）
- 修复首次加载不显示数据问题（requestIdRef 清理时机）
- 修复页码初始值错误（hasMore 默认值）
- 修复后端响应序列化问题（Eloquent 模型转数组）
- 添加审批人和抄送人重复校验
- 修复双 header 问题
- 调整申请页面 padding-bottom

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

backend/app/service/ApprovalService.php

@@ -183,10 +183,12 @@ class ApprovalService
         switch ($type) {
             case 'my':
                 $query->where('applicant_id', $userId);
+                error_log("🔍 Debug 'my' query: userId={$userId}");
                 break;
             case 'pending':
                 // 获取用户待审批的订单
                 $pendingOrderIds = $this->getPendingOrderIds($userId);
+                error_log("🔍 Debug 'pending' query: userId={$userId}, pendingOrderIds=" . json_encode($pendingOrderIds));
                 $query->whereIn('id', $pendingOrderIds);
                 break;
             case 'approved':
@@ -197,19 +199,43 @@ class ApprovalService
                     ->pluck('order_id')
                     ->unique()
                     ->toArray();
+                error_log("🔍 Debug 'approved' query: userId={$userId}, approvedOrderIds=" . json_encode($approvedOrderIds));
                 $query->whereIn('id', $approvedOrderIds)
                     ->whereIn('status', [ApprovalOrder::STATUS_APPROVED, ApprovalOrder::STATUS_REJECTED, ApprovalOrder::STATUS_CANCELLED]);
                 break;
         }
 
         $total = $query->count();
+        error_log("🔍 Debug total count: type={$type}, total={$total}");
+
         $list = $query->orderBy('created_at', 'desc')
             ->offset(($page - 1) * $pageSize)
             ->limit($pageSize)
             ->get();
 
+        error_log("🔍 Debug list count: type={$type}, page={$page}, count=" . $list->count());
+
+        // 转换为数组避免序列化问题
+        $listArray = $list->map(function ($item) {
+            return [
+                'id' => $item->id,
+                'title' => $item->title,
+                'business_type' => $item->business_type,
+                'status' => $item->status,
+                'created_at' => $item->created_at ? $item->created_at->toDateTimeString() : null,
+                'applicant' => $item->applicant ? [
+                    'id' => $item->applicant->id,
+                    'name' => $item->applicant->name,
+                ] : null,
+                'flow' => $item->flow ? [
+                    'id' => $item->flow->id,
+                    'name' => $item->flow->name,
+                ] : null,
+            ];
+        })->toArray();
+
         return [
-            'list' => $list,
+            'list' => $listArray,
             'total' => $total,
             'page' => $page,
             'page_size' => $pageSize,

backend/app/service/BusinessTripService.php

@@ -103,6 +103,26 @@ class BusinessTripService
                 throw new \Exception('当前状态无法提交');
             }
 
+            // 验证审批人和抄送人不能重复
+            $approverIds = array_column($approvers, 'id');
+            $ccUserIds = array_column($ccUsers, 'id');
+
+            // 检查审批人列表中是否有重复
+            if (count($approverIds) !== count(array_unique($approverIds))) {
+                throw new \Exception('审批人列表中有重复用户');
+            }
+
+            // 检查抄送人列表中是否有重复
+            if (count($ccUserIds) !== count(array_unique($ccUserIds))) {
+                throw new \Exception('抄送人列表中有重复用户');
+            }
+
+            // 检查审批人和抄送人是否有重叠
+            $overlap = array_intersect($approverIds, $ccUserIds);
+            if (!empty($overlap)) {
+                throw new \Exception('审批人和抄送人不能是同一个人');
+            }
+
             // 获取审批流程（简化版：直接使用第一个审批人作为单人审批）
             $flow = ApprovalFlow::where('business_type', 'business_trip')
                 ->where('status', 1)