Add backup export/import to the admin panel setup page - #899

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/setup-dotnet@v1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

The event 'SoccerBall.Died' is never used

Do not prefix calls with base unless local implementation exists (https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1100.md)

The default value specified for parameter 'cancellationToken' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments

The default value specified for parameter 'cancellationToken' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments

The default value specified for parameter 'cancellationToken' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments

Component parameter 'MUnique.OpenMU.Web.ItemEditor.MuItemStorage.SelectedItem' should be auto property

The event 'AppearanceData.AppearanceChanged' is never used

A enum should not follow a method (https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1201.md)

Closing brace should be followed by blank line (https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1513.md)