implemented internal file sharing and saving, added server-side file references, refactored share pickers for unified flows, and updated UI branding labels

lib/view/pages/talk/widgets/chat_bubble.dart

@@ -6,6 +6,7 @@ import '../../../../api/marianumcloud/talk/room/get_room_response.dart';
 import '../../../../extensions/date_time.dart';
 import '../../../../extensions/text.dart';
 import '../../../../routing/app_routes.dart';
+import '../../../../share_intent/remote_file_ref.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../../../../utils/download_manager.dart';
 import '../../../../widget/confirm_dialog.dart';
@@ -90,7 +91,14 @@ class _ChatBubbleState extends State<ChatBubble>
     if (status is DownloadDone) {
       DownloadManager.instance.clear(job.remotePath);
       _detachJob();
-      AppRoutes.openFileViewer(context, status.localPath);
+      final talkFile = message.file;
+      AppRoutes.openFileViewer(
+        context,
+        status.localPath,
+        remoteFile: talkFile != null
+            ? RemoteFileRef.fromTalk(talkFile)
+            : null,
+      );
       setState(() {});
     } else if (status is DownloadFailed) {
       final message = status.message;