Enhance documentation with new features: added dark/light/system theme support, instructions page, and application catalog. Updated API and domain model for app management and automatic migrations on startup. Improved frontend structure with new routes and features for user instructions and app management.

backend/src/PnvPanel.Application/Apps/ClientAppDto.cs

@@ -0,0 +1,9 @@
+using PnvPanel.Domain.Apps;
+
+namespace PnvPanel.Application.Apps;
+
+public sealed record ClientAppDto(Guid Id, string Name, string DownloadUrl, string? Description, string? IconUrl)
+{
+    public static ClientAppDto FromDomain(ClientApp app) =>
+        new(app.Id, app.Name, app.DownloadUrl.ToString(), app.Description, app.IconUrl);
+}