Start adding Miniflux support plus other cleanup

- Modernize old async code
- Update to .NET 10
- Adjust namespace
- Bypass update check when debugging

Application/Options/AccountWindow.xaml

@@ -4,10 +4,11 @@
         xmlns:properties="clr-namespace:FeedCenter.Properties"
         xmlns:feedCenter="clr-namespace:FeedCenter"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-        d:DataContext="{d:DesignInstance Type=feedCenter:Account}"
+        d:DataContext="{d:DesignInstance Type=feeds:Account}"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:mah="http://metro.mahapps.com/winfx/xaml/controls"
         xmlns:options="clr-namespace:FeedCenter.Options"
+        xmlns:feeds="clr-namespace:FeedCenter.Feeds"
         mc:Ignorable="d"
         Title="AccountWindow"
         Height="350"