fix: 优化报销创建页面样式与洞察面板交互

修复侧边栏和审计视图样式细节，完善差旅报销洞察面板和消息
组件布局，优化报销创建页面会话管理和流程状态持久化，增强
申请预览工具函数和导航图标，补充单元测试。

web/src/assets/styles/components/sidebar-rail.css

@@ -92,8 +92,9 @@
   z-index: 30;
   width: 28px;
   height: 28px;
-  display: inline-grid;
-  place-items: center;
+  display: flex;
+  align-items: center;
+  justify-content: center;
   cursor: pointer;
   border: 1px solid #dbe4ee;
   border-radius: 999px;
@@ -125,7 +126,17 @@
 
 .rail-collapse-btn .mdi {
   font-size: 17px;
-  line-height: 1;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.rail-collapse-btn .mdi-chevron-left {
+  margin-left: 1px;
+}
+
+.rail-collapse-btn .mdi-chevron-right {
+  margin-right: 1px;
 }
 
 .rail-nav {