feat: implement cloud upload with WebDAV and SFTP support

- Add CloudUploadService with WebDAV and SFTP upload methods
- Add UploadQueueProvider for managing upload queue
- Integrate upload trigger after download completes
- Update CloudSettingsPage with actual connection test and queue UI
- Add webdav_client ^1.2.2 and dartssh2 ^2.13.0 dependencies
- Remove Google Drive option (not implemented)
- Bump version to 3.4.0+72

lib/constants/app_info.dart

@@ -1,8 +1,8 @@
 /// App version and info constants
 /// Update version here only - all other files will reference this
 class AppInfo {
-  static const String version = '3.3.6';
-  static const String buildNumber = '71';
+  static const String version = '3.4.0';
+  static const String buildNumber = '72';
   static const String fullVersion = '$version+$buildNumber';