added a swipeable media gallery for chat and folder images and videos with server previews, on-demand originals and zoom, and marked document previews in chat so they no longer pass for photos

lib/widget/file_viewer.dart

@@ -3,14 +3,12 @@ import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
 
-import 'package:file_picker/file_picker.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 import 'package:open_filex/open_filex.dart';
 import 'package:photo_view/photo_view.dart';
-import 'package:share_plus/share_plus.dart';
 
 import '../routing/app_routes.dart';
 import '../share_intent/remote_file_ref.dart';
@@ -18,16 +16,15 @@ import '../state/app/modules/settings/bloc/settings_cubit.dart';
 import '../utils/downloads/download_manager.dart';
 import '../utils/screen_bound_image.dart';
 import 'app_progress_indicator.dart';
-import 'async_action_button.dart';
 import 'centered_leading.dart';
 import 'downloads/stale_download_guard.dart';
 import 'file_viewer/code_line.dart';
 import 'file_viewer/deferred_pdf_viewer.dart';
 import 'file_viewer/file_kind.dart';
+import 'file_viewer/local_file_actions.dart';
 import 'file_viewer/media_player.dart';
 import 'file_viewer/unknown_preview_block.dart';
 import 'info_dialog.dart';
-import 'share_position_origin.dart';
 
 class FileViewer extends StatefulWidget {
   final String path;
@@ -137,54 +134,11 @@ class _FileViewerState extends State<FileViewer> {
         break;
       case FileViewingActions.share:
         if (!_ensureLocalFile()) return;
-        unawaited(
-          runWithErrorDialog(
-            context,
-            () => SharePlus.instance.share(
-              ShareParams(
-                files: [XFile(widget.path)],
-                sharePositionOrigin: SharePositionOrigin.get(context),
-              ),
-            ),
-          ),
-        );
+        unawaited(shareLocalFile(context, widget.path));
         break;
       case FileViewingActions.save:
         if (!_ensureLocalFile()) return;
-        try {
-          final source = File(widget.path);
-          final size = await source.length();
-          // file_picker has no path/stream save API, so the whole file
-          // gets loaded into RAM. Cap big media; user falls back to share.
-          const maxBytes = 200 * 1024 * 1024;
-          if (size > maxBytes) {
-            if (!mounted) return;
-            InfoDialog.show(
-              context,
-              'Diese Datei ist zu groß (${(size / (1024 * 1024)).toStringAsFixed(0)} MB), '
-              'um direkt gespeichert zu werden. Nutze stattdessen die Teilen-Funktion.',
-              title: 'Speichern nicht möglich',
-            );
-            return;
-          }
-          final bytes = await source.readAsBytes();
-          final saved = await FilePicker.saveFile(
-            fileName: _fileName,
-            bytes: bytes,
-          );
-          if (!mounted) return;
-          if (saved != null) {
-            InfoDialog.show(context, 'Datei gespeichert.');
-          }
-        } on Object catch (e) {
-          if (!mounted) return;
-          InfoDialog.show(
-            context,
-            'Speichern fehlgeschlagen: $e',
-            copyable: true,
-            title: 'Fehler',
-          );
-        }
+        await saveLocalFile(context, widget.path);
         break;
     }
   }