Add horizontal gap to vertical MudTabs between tabbar and panels

MudBlazor 9 renders mud-tabs-vertical with the tabbar flush against the panels
container, making the active tab indicator visually touch the panel content.
Add 16px padding-inline-start on the panels area (and -end for the reverse layout)
so the tabbar and panels have breathing room.

framework/src/Volo.Abp.MudBlazorUI/wwwroot/volo.abp.mudblazorui.css

@@ -98,3 +98,15 @@
     line-height: 1.4rem;
 }
 
+
+/* Vertical MudTabs (Position="Left"/"Right"): add horizontal gap between the tabbar
+   and the panels container so the active tab indicator does not visually touch the
+   panel content. v9 default puts them flush against each other. */
+.mud-tabs.mud-tabs-vertical > .mud-tabs-panels {
+    padding-inline-start: 16px;
+}
+
+.mud-tabs.mud-tabs-vertical-reverse > .mud-tabs-panels {
+    padding-inline-end: 16px;
+}
+