implemented a comprehensive client-side demo mode triggered by a "demo@" username prefix, serving curated fixture data for all app modules

lib/view/pages/files/sharing/share_options_sheet.dart

@@ -11,6 +11,7 @@ import '../../../../state/app/modules/nextcloud_capabilities/bloc/nextcloud_capa
 import '../../../../utils/clipboard_helper.dart';
 import '../../../../widget/centered_leading.dart';
 import '../../../../widget/confirm_dialog.dart';
+import '../../../../widget/demo_restricted.dart';
 import '../../../../widget/details_bottom_sheet.dart';
 import '../../../../widget/info_dialog.dart';
 import 'share_password_sheet.dart';
@@ -35,6 +36,7 @@ void showShareOptionsSheet(
   Share share, {
   required VoidCallback onChanged,
 }) {
+  if (guardDemoAction(context)) return;
   showDetailsBottomSheet(
     context,
     header: ListTile(

lib/view/pages/files/sharing/share_sheet.dart

@@ -13,6 +13,7 @@ import '../../../../state/app/modules/nextcloud_capabilities/bloc/nextcloud_capa
 import '../../../../utils/clipboard_helper.dart';
 import '../../../../widget/app_progress_indicator.dart';
 import '../../../../widget/centered_leading.dart';
+import '../../../../widget/demo_restricted.dart';
 import '../../../../widget/details_bottom_sheet.dart';
 import '../../../../widget/info_dialog.dart';
 import '../widgets/file_leading.dart';
@@ -23,6 +24,7 @@ import 'share_password_sheet.dart';
 /// gated actions to create new ones (public link, user/group). Capability
 /// gating mirrors the Nextcloud web UI.
 void showShareSheet(BuildContext context, CacheableFile file) {
+  if (guardDemoAction(context)) return;
   showDetailsBottomSheet(
     context,
     header: ListTile(

lib/view/pages/files/widgets/add_file_menu.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 
 import '../../../../state/app/modules/files/bloc/files_bloc.dart';
 import '../../../../widget/async_action_button.dart';
+import '../../../../widget/demo_restricted.dart';
 import '../../../../widget/details_bottom_sheet.dart';
 import '../../../../widget/file_pick.dart';
 
@@ -13,6 +14,7 @@ void showAddFileSheet(
   required FilesBloc bloc,
   required Future<void> Function(List<String>? paths) onPickedFiles,
 }) {
+  if (guardDemoAction(context)) return;
   showDetailsBottomSheet(
     context,
     children: (sheetCtx) => [

lib/view/pages/files/widgets/file_element.dart

@@ -15,6 +15,7 @@ import '../../../../utils/file_clipboard.dart';
 import '../../../../utils/haptics.dart';
 import '../../../../widget/centered_leading.dart';
 import '../../../../widget/confirm_dialog.dart';
+import '../../../../widget/demo_restricted.dart';
 import '../../../../widget/details_bottom_sheet.dart';
 import '../../../../widget/downloads/download_trigger.dart';
 import '../../../../widget/info_dialog.dart';
@@ -105,6 +106,7 @@ class _FileElementState extends State<FileElement>
       );
       return;
     }
+    if (guardDemoAction(context)) return;
     if (EndpointData().getEndpointMode() == EndpointMode.stage) {
       InfoDialog.show(
         context,
@@ -135,6 +137,7 @@ class _FileElementState extends State<FileElement>
       isDirectory ? '$folder$name/' : '$folder$name';
 
   Future<void> _rename() async {
+    if (guardDemoAction(context)) return;
     final controller = TextEditingController(text: widget.file.name);
     try {
       final newName = await showDialog<String>(
@@ -182,6 +185,7 @@ class _FileElementState extends State<FileElement>
   }
 
   void _putOnClipboard({required bool copy}) {
+    if (guardDemoAction(context)) return;
     if (copy) {
       FileClipboard.instance.copy([widget.file]);
     } else {
@@ -198,6 +202,7 @@ class _FileElementState extends State<FileElement>
   }
 
   Future<void> _delete() async {
+    if (guardDemoAction(context)) return;
     await showDialog<void>(
       context: context,
       builder: (context) => ConfirmDialog(
@@ -269,6 +274,7 @@ class _FileElementState extends State<FileElement>
             title: const Text('Im Talk-Chat versenden'),
             onTap: () {
               Navigator.of(sheetCtx).pop();
+              if (guardDemoAction(context)) return;
               AppRoutes.openInternalShareToChat(
                 context,
                 RemoteFileRef.fromCacheable(widget.file),