fix: reduce collapsed sidebar item margin and add popup icon gap

- 折叠时菜单项左右 margin 8px→4px，图标放大到 24px
- 折叠弹出的子菜单（teleport 到 body）用全局样式补图标与文字间距

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/ty-sidebar.vue

@@ -6,6 +6,7 @@
         :collapse="collapsed"
         :unique-opened="accordion"
         :collapse-transition="false"
+        popper-class="ty-menu-popper"
         @select="onSelect"
       >
         <template v-for="item in menus" :key="item.code">
@@ -109,9 +110,21 @@ function onSelect(index: string): void {
     }
   }
 
-  .el-menu--collapse :deep(.icon) {
-    margin-right: 0;
-    font-size: 22px;
+  .el-menu--collapse {
+    :deep(.el-menu-item),
+    :deep(.el-sub-menu__title) {
+      margin: 2px 4px;
     }
+
+    :deep(.icon) {
+      margin-right: 0;
+      font-size: 24px;
+    }
+  }
+}
+
+/* 折叠时弹出的子菜单（teleport 到 body，需全局样式）图标与文字间距 */
+:global(.ty-menu-popper .el-menu-item .icon) {
+  margin-right: 8px;
 }
 </style>