fix(file-manager): apply compact density to directory tree (#1478)

* fix(file-manager): apply compact density to directory tree

* test(css): exercise the configured PostCSS plugin chain

plugins/file-manager/src/frontend/FileManager.tsx

@@ -3469,6 +3469,7 @@ function FileManagerContent({
           >
             <div className="flex-1 flex flex-col overflow-hidden min-h-0 border border-border bg-card">
               <FileManagerSidebar
+                density={density}
                 currentHost={currentHost}
                 currentPath={currentPath}
                 onPathChange={navigateTo}