added clear message for denied camera or gallery access

lib/widget/avatar_actions_sheet.dart

@@ -42,7 +42,7 @@ Future<AvatarSheetResult?> showAvatarActionsSheet(
         onTap: () async {
           final bytes = await _pickAndCrop(
             sheetContext,
-            FilePick.singleGalleryPick,
+            () => FilePick.singleGalleryPick(sheetContext),
           );
           if (bytes == null || !sheetContext.mounted) return;
           result = AvatarUploadResult(bytes);
@@ -53,7 +53,10 @@ Future<AvatarSheetResult?> showAvatarActionsSheet(
         leading: const Icon(Icons.photo_camera_outlined),
         title: const Text('Foto aufnehmen'),
         onTap: () async {
-          final bytes = await _pickAndCrop(sheetContext, FilePick.cameraPick);
+          final bytes = await _pickAndCrop(
+            sheetContext,
+            () => FilePick.cameraPick(sheetContext),
+          );
           if (bytes == null || !sheetContext.mounted) return;
           result = AvatarUploadResult(bytes);
           Navigator.of(sheetContext).pop();

lib/widget/chat_background_picker_sheet.dart

@@ -21,7 +21,9 @@ Future<Uint8List?> showChatBackgroundPickerSheet(BuildContext context) async {
         leading: const Icon(Icons.photo_library_outlined),
         title: const Text('Aus Galerie wählen'),
         onTap: () async {
-          final bytes = await _pickRaw(FilePick.singleGalleryPick);
+          final bytes = await _pickRaw(
+            () => FilePick.singleGalleryPick(sheetContext),
+          );
           if (bytes == null || !sheetContext.mounted) return;
           result = bytes;
           Navigator.of(sheetContext).pop();
@@ -31,7 +33,7 @@ Future<Uint8List?> showChatBackgroundPickerSheet(BuildContext context) async {
         leading: const Icon(Icons.photo_camera_outlined),
         title: const Text('Foto aufnehmen'),
         onTap: () async {
-          final bytes = await _pickRaw(FilePick.cameraPick);
+          final bytes = await _pickRaw(() => FilePick.cameraPick(sheetContext));
           if (bytes == null || !sheetContext.mounted) return;
           result = bytes;
           Navigator.of(sheetContext).pop();

lib/widget/file_pick.dart

@@ -1,22 +1,77 @@
+import 'package:app_settings/app_settings.dart';
 import 'package:file_picker/file_picker.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:image_picker/image_picker.dart';
 
+import '../api/errors/error_mapper.dart';
+import '../api/errors/permission_exception.dart';
+import 'confirm_dialog.dart';
+import 'info_dialog.dart';
+
+/// Thin wrapper around the platform pickers. Every method resolves to `null`
+/// when the user cancels **or** when picking failed; failures are reported to
+/// the user right here (permission denial with a shortcut to the system
+/// settings, everything else as a plain error dialog) so call sites can treat
+/// the result like a cancel.
 class FilePick {
   static final _picker = ImagePicker();
 
-  static Future<List<XFile>?> multipleGalleryPick() async {
-    final pickedImages = await _picker.pickMultiImage();
-    return pickedImages.isNotEmpty ? pickedImages : null;
-  }
+  static Future<List<XFile>?> multipleGalleryPick(BuildContext context) =>
+      _guarded(context, () async {
+        final pickedImages = await _picker.pickMultiImage();
+        return pickedImages.isNotEmpty ? pickedImages : null;
+      });
 
-  static Future<XFile?> singleGalleryPick() =>
-      _picker.pickImage(source: ImageSource.gallery);
+  static Future<XFile?> singleGalleryPick(BuildContext context) =>
+      _guarded(context, () => _picker.pickImage(source: ImageSource.gallery));
 
-  static Future<XFile?> cameraPick() =>
-      _picker.pickImage(source: ImageSource.camera);
+  static Future<XFile?> cameraPick(BuildContext context) =>
+      _guarded(context, () => _picker.pickImage(source: ImageSource.camera));
 
   static Future<List<String>?> documentPick() async {
     final result = await FilePicker.pickFiles(allowMultiple: true);
     return result?.files.map((e) => e.path).nonNulls.toList();
   }
+
+  static Future<T?> _guarded<T>(
+    BuildContext context,
+    Future<T?> Function() pick,
+  ) async {
+    try {
+      return await pick();
+    } on PlatformException catch (e) {
+      final denied = PermissionException.fromPlatform(e);
+      if (!context.mounted) return null;
+      if (denied != null) {
+        _showPermissionDialog(context, denied);
+      } else {
+        _showErrorDialog(context, e);
+      }
+      return null;
+    } catch (e) {
+      if (context.mounted) _showErrorDialog(context, e);
+      return null;
+    }
+  }
+
+  static void _showPermissionDialog(
+    BuildContext context,
+    PermissionException denied,
+  ) => ConfirmDialog(
+    icon: Icons.block_outlined,
+    title: 'Zugriff verweigert',
+    content: denied.userMessage,
+    confirmButton: 'Einstellungen öffnen',
+    onConfirm: AppSettings.openAppSettings,
+  ).asDialog(context);
+
+  static void _showErrorDialog(BuildContext context, Object error) {
+    final message = errorToUserMessage(error);
+    final details = errorToTechnicalDetails(error);
+    final body = details != null && details != message
+        ? '$message\n\n$details'
+        : message;
+    InfoDialog.show(context, body, copyable: true, title: 'Fehler');
+  }
 }