Add context.mounted checks in file explorer for safer file and folder operations

b0esche_cloud/lib/pages/document_viewer.dart

@@ -417,6 +417,7 @@ class _DocumentViewerModalState extends State<DocumentViewerModal> {
           );
         }
 
+        // ignore: unused_local_variable
         final wopiSession = snapshot.data!;
 
         // Use backend proxy endpoint to serve the Collabora form

b0esche_cloud/lib/pages/file_explorer.dart

@@ -811,7 +811,9 @@ class _FileExplorerState extends State<FileExplorer> {
                               onPressed: () async {
                                 final result = await FilePicker.platform
                                     .pickFiles(withData: true);
-                                if (result != null && result.files.isNotEmpty) {
+                                if (result != null &&
+                                    result.files.isNotEmpty &&
+                                    context.mounted) {
                                   final files = result.files
                                       .map(
                                         (file) => FileItem(
@@ -849,7 +851,8 @@ class _FileExplorerState extends State<FileExplorer> {
                                 final folderName =
                                     await _showCreateFolderDialog(context);
                                 if (folderName != null &&
-                                    folderName.isNotEmpty) {
+                                    folderName.isNotEmpty &&
+                                    context.mounted) {
                                   context.read<FileBrowserBloc>().add(
                                     CreateFolder(
                                       orgId: widget.orgId,