feat: 新增预算助手报告组件并优化报销交互细节

新增预算助手报告视图模型和组件，优化报销洞察面板和消息项
样式细节，完善预算中心页面布局和文档中心视图，增强报销创
建会话管理和提交编排器，调整 Vite 构建配置，补充单元测试。

web/src/assets/styles/views/budget-center-view.css

@@ -265,6 +265,46 @@
   font-weight: 800;
 }
 
+.budget-table-search {
+  position: relative;
+  width: min(260px, 42%);
+  min-width: 190px;
+  display: flex;
+  align-items: center;
+}
+
+.budget-table-search i {
+  position: absolute;
+  left: 11px;
+  color: #94a3b8;
+  font-size: 15px;
+  pointer-events: none;
+}
+
+.budget-table-search input {
+  width: 100%;
+  height: 32px;
+  border: 1px solid #dbe4ee;
+  border-radius: 6px;
+  padding: 0 11px 0 32px;
+  background: #fff;
+  color: #1f2937;
+  font-size: 13px;
+  font-weight: 650;
+  outline: none;
+  transition: border-color 160ms ease, box-shadow 160ms ease;
+}
+
+.budget-table-search input::placeholder {
+  color: #94a3b8;
+  font-weight: 500;
+}
+
+.budget-table-search input:focus {
+  border-color: rgba(var(--theme-primary-rgb), .48);
+  box-shadow: 0 0 0 3px rgba(var(--theme-primary-rgb), .1);
+}
+
 .department-search {
   position: relative;
   margin: 12px 14px 8px;
@@ -320,7 +360,7 @@
 
 .budget-table-panel table {
   width: 100%;
-  min-width: 1040px;
+  min-width: 1460px;
   border-collapse: collapse;
 }
 
@@ -383,29 +423,36 @@
   background: var(--danger);
 }
 
-.budget-warning-red {
-  color: var(--danger) !important;
-  font-weight: 800;
+.budget-threshold-cell {
+  padding-left: 12px !important;
+  padding-right: 12px !important;
 }
 
-.budget-warning-yellow {
-  color: var(--warning-active) !important;
-  font-weight: 800;
-}
-
-.budget-row-actions {
-  display: flex;
+.budget-threshold-badge {
+  min-width: 58px;
+  display: inline-flex;
   align-items: center;
   justify-content: center;
-  gap: 14px;
+  padding: 4px 9px;
+  border-radius: 999px;
+  font-size: 12px;
+  font-weight: 800;
+  line-height: 1.2;
 }
 
-.budget-row-actions button {
-  border: 0;
-  background: transparent;
-  color: var(--theme-primary-active);
-  font-size: 14px;
-  font-weight: 800;
+.budget-threshold-badge.reminder {
+  background: rgba(37, 99, 235, .1);
+  color: #2563eb;
+}
+
+.budget-threshold-badge.alert {
+  background: rgba(245, 158, 11, .14);
+  color: #b45309;
+}
+
+.budget-threshold-badge.risk {
+  background: rgba(127, 29, 29, .1);
+  color: #7f1d1d;
 }
 
 .budget-table-foot {