feat: complete Sprint 3 Expo mobile app scaffold + all screens

app/(app)/installations/[id].tsx

@@ -0,0 +1,83 @@
+import { useState } from 'react';
+import { View, Text, TouchableOpacity, ScrollView, Alert, Image, ActivityIndicator } from 'react-native';
+import { useLocalSearchParams, router } from 'expo-router';
+import * as ImagePicker from 'expo-image-picker';
+import * as Location from 'expo-location';
+import { api } from '../../../services/api';
+
+export default function InstallationConfirmScreen() {
+  const { id } = useLocalSearchParams<{ id: string }>();
+  const [photo, setPhoto] = useState<string | null>(null);
+  const [coords, setCoords] = useState<{ lat: number; lng: number } | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [gpsLoading, setGpsLoading] = useState(false);
+
+  const capturePhoto = async () => {
+    const { status } = await ImagePicker.requestCameraPermissionsAsync();
+    if (status !== 'granted') return Alert.alert('Permission denied', 'Camera access is required.');
+    const result = await ImagePicker.launchCameraAsync({ quality: 0.7, base64: false });
+    if (!result.canceled) setPhoto(result.assets[0].uri);
+  };
+
+  const captureGPS = async () => {
+    setGpsLoading(true);
+    try {
+      const { status } = await Location.requestForegroundPermissionsAsync();
+      if (status !== 'granted') { Alert.alert('Permission denied', 'Location access is required.'); return; }
+      const loc = await Location.getCurrentPositionAsync({ accuracy: Location.Accuracy.High });
+      setCoords({ lat: loc.coords.latitude, lng: loc.coords.longitude });
+    } catch { Alert.alert('Error', 'Could not get location.'); }
+    finally { setGpsLoading(false); }
+  };
+
+  const confirm = async () => {
+    if (!coords) return Alert.alert('Required', 'Capture GPS location first.');
+    setLoading(true);
+    try {
+      await api.patch(`/api/v1/tickets/${id}/confirm-installation`, {
+        latitude: coords.lat,
+        longitude: coords.lng,
+        photoUrl: photo,
+      });
+      Alert.alert('Done!', 'Installation confirmed.', [{ text: 'OK', onPress: () => router.back() }]);
+    } catch (e: any) {
+      Alert.alert('Error', e?.response?.data?.message ?? 'Confirmation failed.');
+    } finally { setLoading(false); }
+  };
+
+  return (
+    <View className="flex-1 bg-gray-50">
+      <View className="px-4 pt-14 pb-4 bg-primary flex-row items-center">
+        <TouchableOpacity onPress={() => router.back()} className="mr-3">
+          <Text className="text-white text-lg">←</Text>
+        </TouchableOpacity>
+        <Text className="text-white text-xl font-bold">Installation Confirmation</Text>
+      </View>
+      <ScrollView className="flex-1 px-4 py-6">
+        <View className="bg-white rounded-2xl border border-gray-100 p-4 mb-4">
+          <Text className="font-semibold text-gray-700 mb-3">📍 GPS Location</Text>
+          {coords ? (
+            <Text className="text-green-700 font-medium">✓ {coords.lat.toFixed(6)}, {coords.lng.toFixed(6)}</Text>
+          ) : (
+            <Text className="text-gray-400 mb-3">No location captured yet</Text>
+          )}
+          <TouchableOpacity className="bg-primary rounded-xl py-3 items-center mt-3" onPress={captureGPS} disabled={gpsLoading}>
+            {gpsLoading ? <ActivityIndicator color="white" /> : <Text className="text-white font-semibold">Capture GPS</Text>}
+          </TouchableOpacity>
+        </View>
+
+        <View className="bg-white rounded-2xl border border-gray-100 p-4 mb-8">
+          <Text className="font-semibold text-gray-700 mb-3">📷 Photo Proof</Text>
+          {photo && <Image source={{ uri: photo }} className="w-full h-48 rounded-xl mb-3" resizeMode="cover" />}
+          <TouchableOpacity className="border border-primary rounded-xl py-3 items-center" onPress={capturePhoto}>
+            <Text className="text-primary font-semibold">{photo ? 'Retake Photo' : 'Take Photo'}</Text>
+          </TouchableOpacity>
+        </View>
+
+        <TouchableOpacity className="bg-green-600 rounded-xl py-4 items-center" onPress={confirm} disabled={loading}>
+          {loading ? <ActivityIndicator color="white" /> : <Text className="text-white font-bold text-base">✓ Confirm Installation</Text>}
+        </TouchableOpacity>
+      </ScrollView>
+    </View>
+  );
+}