very basics of auth state - not actually authenticating anything right now....

app/_layout.tsx

@@ -1,9 +1,29 @@
 import { Stack } from 'expo-router'
+import { SessionProvider, useSession } from './ctx'
+import { SplashScreenController } from './splash'
 
-export default function RootLayout() {
+export default function Root() {
+    // Set up the auth context and render our layout inside of it.
+    return (
+        <SessionProvider>
+            <SplashScreenController />
+            <RootNavigator />
+        </SessionProvider>
+    )
+}
+
+// Separate this into a new component so it can access the SessionProvider context later
+function RootNavigator() {
+    const { session } = useSession()
     return (
         <Stack>
-            <Stack.Screen name='(tabs)' options={{ headerShown: false }}></Stack.Screen>
+            <Stack.Protected guard={!!session}>
+                <Stack.Screen options={{ headerShown: false }} name='(tabs)' />
+            </Stack.Protected>
+
+            <Stack.Protected guard={!session}>
+                <Stack.Screen options={{ headerShown: false }} name='login' />
+            </Stack.Protected>
         </Stack>
     )
 }