feat: Sprint 1 — Onboarding screen, user persistence, Contact management (list, add, edit, delete, detail, search, filter)

app/_layout.tsx

@@ -1,11 +1,49 @@
+// app/_layout.tsx
 import { Stack } from 'expo-router';
 import { GestureHandlerRootView } from 'react-native-gesture-handler';
+import { useEffect, useState } from 'react';
+import { View, ActivityIndicator } from 'react-native';
+import { useUserStore } from '@/store/useUserStore';
+import { getDatabase } from '@/lib/database';
 import '../global.css';
 
 export default function RootLayout() {
+  const [loading, setLoading] = useState(true);
+  const setUser = useUserStore((s) => s.setUser);
+
+  useEffect(() => {
+    async function bootstrap() {
+      try {
+        const db = await getDatabase();
+        const user = await db.getFirstAsync<{ id: string; display_name: string; share_id: string }>(
+          'SELECT id, display_name, share_id FROM users WHERE is_self = 1 LIMIT 1'
+        );
+        if (user) {
+          setUser({ id: user.id, displayName: user.display_name, shareId: user.share_id });
+        }
+      } catch (e) {
+        console.error('Bootstrap error:', e);
+      } finally {
+        setLoading(false);
+      }
+    }
+    bootstrap();
+  }, []);
+
+  if (loading) {
+    return (
+      <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center', backgroundColor: '#F8F4EF' }}>
+        <ActivityIndicator size="large" color="#1A6B72" />
+      </View>
+    );
+  }
+
   return (
     <GestureHandlerRootView style={{ flex: 1 }}>
-      <Stack screenOptions={{ headerShown: false }} />
+      <Stack screenOptions={{ headerShown: false }}>
+        <Stack.Screen name="onboarding" />
+        <Stack.Screen name="(tabs)" />
+      </Stack>
     </GestureHandlerRootView>
   );
 }