fix: widen collapsed sidebar to 64px, prevent header flash on refresh

Collapsed width 56px→64px to stop clipping site picker badge and icons.
Return null while auth is loading on site pages to prevent brief flash
of the public floating header before the sidebar layout renders.

app/layout-content.tsx

@@ -95,7 +95,12 @@ function LayoutInner({ children }: { children: React.ReactNode }) {
     return <LoadingOverlay logoSrc="/pulse_icon_no_margins.png" title="Pulse" portal={false} />
   }
 
-  // Authenticated site pages: full Dokploy-style layout (sidebar + utility bar)
+  // While auth is loading on a site page, render nothing to prevent flash of public header
+  if (auth.loading && isSitePage) {
+    return null
+  }
+
+  // Authenticated site pages: full sidebar layout
   // DashboardShell inside children handles everything
   if (isAuthenticated && isSitePage) {
     return (