Show the cluster's solar weather in a bandmap status bar

The reader follows N1MM's rules for WWV and WCY lines and the sh/wwv
table. The bar is hidden until the cluster has sent some.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Nonemm.App/AppSession.cs

@@ -914,6 +914,7 @@ public sealed partial class AppSession : IDisposable
     public void ConnectCluster()
     {
         cluster?.Dispose();
+        SetSolar("");
         cluster = new ClusterClient(
             Settings.ClusterHost,
             Settings.ClusterPort,
@@ -923,14 +924,28 @@ public sealed partial class AppSession : IDisposable
             autoLogon: Settings.ClusterAutoLogon,
             keepAliveInterval: TimeSpan.FromMinutes(Math.Max(1, Settings.ClusterKeepAliveMinutes)));
         cluster.SpotArrived += (_, spot) => TakeSpot(spot);
+        cluster.SolarArrived += (_, text) => SetSolar(text);
         cluster.ConnectionChanged += (_, _) => Changed?.Invoke(this, EventArgs.Empty);
         cluster.Start();
     }
 
+    /// The latest solar weather the cluster sent, or empty when it has sent
+    /// none on this connection.
+    public string Solar { get; private set; } = "";
+
+    public event EventHandler? SolarChanged;
+
+    private void SetSolar(string text)
+    {
+        Solar = text;
+        SolarChanged?.Invoke(this, EventArgs.Empty);
+    }
+
     public void DisconnectCluster()
     {
         cluster?.Dispose();
         cluster = null;
+        SetSolar("");
         Changed?.Invoke(this, EventArgs.Empty);
     }
 

src/Nonemm.App/Windows/BandmapWindow.axaml

@@ -8,6 +8,10 @@
       <ComboBox Name="SpanBox" FontSize="11" Width="96" />
       <CheckBox Name="CentreBox" Content="Centre on VFO" FontSize="11" Margin="8,0,0,0" />
     </DockPanel>
+    <Border Name="SolarBar" DockPanel.Dock="Bottom" IsVisible="False" Padding="6,2"
+            BorderThickness="0,1,0,0" BorderBrush="Gray">
+      <TextBlock Name="SolarText" FontSize="11" TextWrapping="Wrap" />
+    </Border>
     <local:BandmapView Name="View" />
   </DockPanel>
 </local:RefreshableWindow>

src/Nonemm.App/Windows/BandmapWindow.axaml.cs

@@ -76,9 +76,21 @@ public sealed partial class BandmapWindow : RefreshableWindow
         };
         View.FrequencyPicked += (_, frequency) => tune(frequency, "");
         session.Bandmap.Changed += (_, _) => Dispatcher.UIThread.Post(Refresh);
+        EventHandler solarChanged = (_, _) => Dispatcher.UIThread.Post(ShowSolar);
+        session.SolarChanged += solarChanged;
+        Closed += (_, _) => session.SolarChanged -= solarChanged;
+        ShowSolar();
         Refresh();
     }
 
+    /// The status bar holds the solar weather the cluster sent, and is hidden
+    /// while there is none.
+    private void ShowSolar()
+    {
+        SolarText.Text = session.Solar;
+        SolarBar.IsVisible = session.Solar.Length > 0;
+    }
+
     private void SaveView()
     {
         session.Save(session.Settings with