simplified code across the app and consolidated duplicated helpers

lib/widget/chat_background_picker_sheet.dart

@@ -1,7 +1,6 @@
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
-import 'package:image_picker/image_picker.dart';
 
 import '../routing/app_routes.dart';
 import 'details_bottom_sheet.dart';
@@ -16,32 +15,8 @@ Future<Uint8List?> showChatBackgroundPickerSheet(BuildContext context) async {
   Uint8List? result;
   await showDetailsBottomSheet(
     context,
-    children: (sheetContext) => [
-      ListTile(
-        leading: const Icon(Icons.photo_library_outlined),
-        title: const Text('Aus Galerie wählen'),
-        onTap: () async {
-          final bytes = await _pickRaw(
-            () => FilePick.singleGalleryPick(sheetContext, forCrop: true),
-          );
-          if (bytes == null || !sheetContext.mounted) return;
-          result = bytes;
-          Navigator.of(sheetContext).pop();
-        },
-      ),
-      ListTile(
-        leading: const Icon(Icons.photo_camera_outlined),
-        title: const Text('Foto aufnehmen'),
-        onTap: () async {
-          final bytes = await _pickRaw(
-            () => FilePick.cameraPick(sheetContext, forCrop: true),
-          );
-          if (bytes == null || !sheetContext.mounted) return;
-          result = bytes;
-          Navigator.of(sheetContext).pop();
-        },
-      ),
-    ],
+    children: (sheetContext) =>
+        imageSourceTiles(sheetContext, onPicked: (bytes) => result = bytes),
   );
   return result;
 }
@@ -53,9 +28,3 @@ Future<Uint8List?> cropChatBackgroundImage(
   BuildContext context,
   Uint8List bytes,
 ) => AppRoutes.openAvatarCrop(context, imageBytes: bytes, aspectRatio: null);
-
-Future<Uint8List?> _pickRaw(Future<XFile?> Function() pick) async {
-  final picked = await pick();
-  if (picked == null) return null;
-  return picked.readAsBytes();
-}