refactor: defer shop validation in Booking pages to allow optional chaining of shop properties

src/pages/Booking.tsx

@@ -45,17 +45,6 @@ export default function Booking() {
     { label: '24 horas', value: 1440 },
   ];
 
-  if (!shop) {
-    return (
-      <SafeAreaView style={styles.container}>
-        <Text>Barbearia não encontrada</Text>
-      </SafeAreaView>
-    );
-  }
-
-  const selectedService = shop.services.find((s) => s.id === serviceId);
-  const selectedBarber = shop.barbers.find((b) => b.id === barberId);
-
   // Geração de datas (próximos 14 dias)
   const availableDates = useMemo(() => {
     const dates = [];
@@ -72,6 +61,9 @@ export default function Booking() {
     return dates;
   }, []);
 
+  const selectedService = shop?.services.find((s) => s.id === serviceId);
+  const selectedBarber = shop?.barbers.find((b) => b.id === barberId);
+
   const generateDefaultSlots = (): string[] => {
     const slots: string[] = [];
     for (let hour = 9; hour <= 18; hour++) {
@@ -103,6 +95,14 @@ export default function Booking() {
     });
   }, [selectedBarber, date, barberId, appointments, slot]);
 
+  if (!shop) {
+    return (
+      <SafeAreaView style={styles.container}>
+        <Text>Barbearia não encontrada</Text>
+      </SafeAreaView>
+    );
+  }
+
   const canNext = () => {
     if (step === 1) return !!serviceId;
     if (step === 2) return !!barberId;