Fix: Show personalised price on design review page

Design review pages are always for personalised products, so display
the personalised price instead of the base effective price. This ensures
the preview page shows the same price that will be charged at checkout.

src/app/designs/[id]/review/page.tsx

@@ -13,7 +13,7 @@ interface DesignApproval {
     id: string;
     name: string;
     basePrice: number;
-    personalisedPrice: number;
+    personalisedPrice: number | null;
     effectivePrice: number;
   };
   designJson: string;
@@ -165,7 +165,7 @@ export default function DesignReviewPage({ params }: { params: { id: string } })
                 </p>
               )}
               <p className="border-t border-line pt-3">
-                <strong>Price:</strong> £{(design.product.effectivePrice / 100).toFixed(2)}
+                <strong>Price:</strong> £{((design.product.personalisedPrice ?? design.product.effectivePrice) / 100).toFixed(2)}
               </p>
             </div>