Add the Avalonia application and the station network

The entry window types contacts and colours them as they are typed; the log,
check, bandmap, score and packet windows read the same session. Contacts are
shared with the other stations of a multi-operator entry in N1MM's contact
message, so an N1MM station on the same network sees them too.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/Nonemm.App/Windows/BandmapWindow.axaml

@@ -0,0 +1,13 @@
+<local:RefreshableWindow xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:local="using:Nonemm.App.Windows"
+        x:Class="Nonemm.App.Windows.BandmapWindow"
+        Title="Bandmap" Width="320" Height="520">
+  <DockPanel>
+    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="6,6,6,2" Spacing="6">
+      <TextBlock Name="BandText" FontSize="12" VerticalAlignment="Center" />
+      <CheckBox Name="ThisBandOnly" Content="this band" IsChecked="True" FontSize="11" />
+    </StackPanel>
+    <ListBox Name="Spots" FontFamily="monospace" FontSize="13" />
+  </DockPanel>
+</local:RefreshableWindow>