Add server-side folders and files page UI (#6383)

frontend/editor/src/core/utils/homePageNavigation.ts

@@ -19,6 +19,12 @@ export function getStartupNavigationAction(
     return null;
   }
 
+  // The user is browsing their file library - don't auto-switch them out of
+  // the file manager just because a new upload landed.
+  if (currentWorkbench === "myFiles") {
+    return null;
+  }
+
   // Already actively viewing in the viewer → update to the latest file
   if (
     previousFileCount > 0 &&