feat: Add import functionality to ExportManager and related components

- Introduced ImportJob and ImportItem structures to handle import tasks.
- Enhanced ExportManagerThread to support import operations, including job queuing and progress tracking.
- Updated ServiceManager to facilitate file imports with optional AFC client handling.
- Modified ImageLoader and ImageTask to accommodate alternative AFC client for image loading.
- Implemented UI updates in StatusBalloon to reflect import process status alongside export.
- Refactored existing code to improve readability and maintainability, including the removal of unused variables and comments.
- Added a new loading icon label for better user feedback during import operations.
- Updated gallery widget to streamline export item creation by removing unnecessary index tracking.
- Enhanced error handling and logging for file operations during import and export processes.

src/exportalbum.cpp

@@ -115,7 +115,6 @@ void ExportAlbum::getTotalPhotoCount(const QStringList &paths)
                 errorOccurred = true;
                 idevice_error_free(err);
             } else {
-                int index = 0;
                 for (size_t i = 0; i < innerCount; ++i) {
                     const char *item = items[i];
                     if (!item) {
@@ -130,8 +129,7 @@ void ExportAlbum::getTotalPhotoCount(const QStringList &paths)
                     QString filePath = path + "/" + QString::fromUtf8(item);
 
                     m_exportItems.append(
-                        ExportItem(filePath, fileName, m_device->udid, index));
-                    ++index;
+                        ExportItem(filePath, fileName, m_device->udid));
                 }
                 free_directory_listing(items, innerCount);
                 count += innerCount;