feat(mobile): track mobile app scaffold

mobile/app/src/platform/camera/receiptCapture.ts

@@ -0,0 +1,55 @@
+import * as ImagePicker from 'expo-image-picker';
+
+export type CapturedReceipt = {
+  uri: string;
+  fileName: string;
+  mimeType?: string;
+  source: 'camera' | 'library';
+};
+
+function toReceipt(asset: ImagePicker.ImagePickerAsset, source: CapturedReceipt['source']): CapturedReceipt {
+  return {
+    uri: asset.uri,
+    fileName: asset.fileName || `receipt-${Date.now()}.jpg`,
+    mimeType: asset.mimeType,
+    source,
+  };
+}
+
+export async function captureReceiptFromCamera(): Promise<CapturedReceipt | null> {
+  const permission = await ImagePicker.requestCameraPermissionsAsync();
+  if (!permission.granted) {
+    throw new Error('需要相机权限才能拍摄票据。');
+  }
+
+  const result = await ImagePicker.launchCameraAsync({
+    allowsEditing: false,
+    quality: 0.84,
+    mediaTypes: ['images'],
+  });
+
+  if (result.canceled || !result.assets[0]) {
+    return null;
+  }
+
+  return toReceipt(result.assets[0], 'camera');
+}
+
+export async function pickReceiptFromLibrary(): Promise<CapturedReceipt | null> {
+  const permission = await ImagePicker.requestMediaLibraryPermissionsAsync();
+  if (!permission.granted) {
+    throw new Error('需要相册权限才能选择票据图片。');
+  }
+
+  const result = await ImagePicker.launchImageLibraryAsync({
+    allowsEditing: false,
+    quality: 0.88,
+    mediaTypes: ['images'],
+  });
+
+  if (result.canceled || !result.assets[0]) {
+    return null;
+  }
+
+  return toReceipt(result.assets[0], 'library');
+}