fix: 修复页面间状态丢失问题并优化选择页面

- 修复选择审批人后再选择抄送人导致状态丢失的问题
- 使用独立的 sessionStorage key (selectedApprovers, selectedCc)
- 组件每次挂载时从 sessionStorage 恢复状态
- 只在提交/保存成功后清除 sessionStorage
- 优化人员选择页面布局和样式
- 更新 CLAUDE.md 文档记录问题和解决方案

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

frontend/src/pages/business-trip/list.module.css

@@ -1,32 +1,97 @@
 .list {
-  padding: 16px;
-}
-
-.tabs {
-  display: flex;
-  gap: 8px;
-  margin-bottom: 16px;
-}
-
-.tab {
-  flex: 1;
-  padding: 8px 12px;
-  border: none;
+  min-height: 100vh;
   background: #f5f5f5;
-  border-radius: 6px;
+  padding-bottom: 60px;
+}
+
+.item {
+  padding: 12px 16px !important;
+}
+
+.card {
+  background: #fff;
+  border-radius: 8px;
+  overflow: hidden;
+}
+
+.header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 12px;
+}
+
+.reason {
+  font-size: 16px;
+  font-weight: 500;
+  color: #333;
+  flex: 1;
+  margin-right: 12px;
+}
+
+.content {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.info {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+}
+
+.date {
   font-size: 14px;
   color: #666;
-  cursor: pointer;
 }
 
-.tab.active {
-  background: #1677ff;
-  color: #fff;
+.days {
+  font-size: 14px;
+  color: #999;
+}
+
+.destination {
+  font-size: 14px;
+  color: #666;
+}
+
+.applicant {
+  font-size: 14px;
+  color: #999;
 }
 
 .empty {
-  padding: 60px 0;
-  text-align: center;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 80px 20px;
   color: #999;
+}
+
+.empty p {
+  margin: 16px 0 24px;
   font-size: 14px;
 }
+
+.fab {
+  position: fixed;
+  right: 20px;
+  bottom: 80px;
+  z-index: 100;
+}
+
+.fab button {
+  width: 50px;
+  height: 50px;
+  border-radius: 50%;
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+}
+
+:global(.adm-tabs-header) {
+  background: #fff;
+  position: sticky;
+  top: 0;
+  z-index: 10;
+}