added support for simultan downloads in files and talk, support for background downloads, enhanced loading in files with retry

lib/state/app/modules/files/bloc/files_bloc.dart

@@ -96,6 +96,10 @@ class FilesBloc
           );
           add(Emit((s) => s.copyWith(listing: cached)));
         },
+        onRetry: (next, max) {
+          if (isStale()) return;
+          add(LoadingStatus('Erneuter Versuch ($next von $max) …'));
+        },
         onError: (e) => capturedError = e,
       );
     } catch (e) {