fix(web): clear needsSetup state after OOBE completion to prevent loop

When SetupWizard completes POST /api/setup and navigates to /admin,
App.tsx still has needsSetup=true in React state, causing an immediate
redirect back to /setup. Pass onSetupComplete callback to SetupWizard
which clears the state before navigating, breaking the loop.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/src/App.tsx

@@ -231,7 +231,7 @@ export function App() {
   if (location.pathname === "/setup") {
     return (
       <BrandingProvider>
-        <SetupWizard />
+        <SetupWizard onSetupComplete={() => setNeedsSetup(false)} />
       </BrandingProvider>
     );
   }