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>
     );
   }

apps/web/src/pages/SetupWizard.jsx

@@ -2,7 +2,7 @@ import { useState, useEffect } from "react";
 import { useNavigate } from "react-router-dom";
 import { useBranding } from "../BrandingContext.js";
 
-export function SetupWizard() {
+export function SetupWizard({ onSetupComplete }) {
   const navigate = useNavigate();
   const { refresh: refreshBranding } = useBranding();
 
@@ -160,6 +160,8 @@ export function SetupWizard() {
         }
         // Refresh branding so the nav bar shows the new business name
         refreshBranding();
+        // Clear needsSetup state in App so the redirect to /admin sticks
+        if (onSetupComplete) onSetupComplete();
       } catch (e) {
         setError("Network error. Please try again.");
         setLoading(false);