feat: Expo scaffold + auth screens + core screens (#39-#46, #48)

app/_layout.tsx

@@ -0,0 +1,31 @@
+import '../global.css';
+import { useEffect } from 'react';
+import { Stack, router } from 'expo-router';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { useAuthStore } from '../stores/authStore';
+
+const queryClient = new QueryClient();
+
+export default function RootLayout() {
+  const { hydrate, token, isLoading } = useAuthStore();
+
+  useEffect(() => {
+    hydrate();
+  }, []);
+
+  useEffect(() => {
+    if (!isLoading) {
+      if (token) {
+        router.replace('/(app)/dashboard');
+      } else {
+        router.replace('/(auth)/company-code');
+      }
+    }
+  }, [isLoading, token]);
+
+  return (
+    <QueryClientProvider client={queryClient}>
+      <Stack screenOptions={{ headerShown: false }} />
+    </QueryClientProvider>
+  );
+}