后台侧栏按业务分组支持折叠

新增后台侧栏业务分组与当前页自动展开行为

补充折叠交互、路由分组和权限过滤测试

同步后台导航分组行为文档

apps/admin-web/src/styles/admin.css

@@ -289,7 +289,66 @@ button:disabled {
 
 .admin-nav {
   display: grid;
-  gap: 8px;
+  gap: 12px;
+}
+
+.admin-nav-group {
+  display: grid;
+  gap: 4px;
+}
+
+.admin-nav-group-toggle {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  min-height: 28px;
+  border: 0;
+  border-radius: 6px;
+  padding: 0 8px;
+  color: #a08472;
+  background: transparent;
+  font-size: 11px;
+  font-weight: 800;
+  letter-spacing: 0.04em;
+  text-align: left;
+  cursor: pointer;
+}
+
+.admin-nav-group-toggle svg {
+  flex: 0 0 auto;
+  transition: transform 160ms ease;
+}
+
+.admin-nav-group[data-collapsed='true'] .admin-nav-group-toggle svg {
+  transform: rotate(-90deg);
+}
+
+.admin-nav-group-toggle small {
+  min-width: 18px;
+  margin-left: auto;
+  border-radius: 999px;
+  padding: 2px 5px;
+  color: #b18d76;
+  background: #faf0e8;
+  font-size: 10px;
+  line-height: 1.2;
+  text-align: center;
+}
+
+.admin-nav-group-toggle:hover,
+.admin-nav-group-toggle:focus-visible {
+  color: #8f3f27;
+  background: #fff8f2;
+  outline: none;
+}
+
+.admin-nav-group-items {
+  display: grid;
+  gap: 4px;
+}
+
+.admin-nav-group-items[data-collapsed='true'] {
+  display: none;
 }
 
 .admin-nav-button,
@@ -305,8 +364,8 @@ button:disabled {
 .admin-nav-button {
   justify-content: flex-start;
   gap: 10px;
-  min-height: 42px;
-  padding: 0 12px;
+  min-height: 40px;
+  padding: 0 12px 0 28px;
   color: #755a49;
   background: transparent;
 }