Make the telnet traffic a compact terminal view

Lines were as tall as a list item, with padding of more than the text. A
line is now as tall as its text, the view always follows the newest line
instead of pausing under the pointer, and a burst of lines is scrolled
once. The scrollback is a thousand lines.

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

src/Nonemm.App/Windows/TelnetWindow.axaml

@@ -9,16 +9,20 @@
       <Setter Property="Opacity" Value="0.7" />
       <Setter Property="Margin" Value="0,6,0,1" />
     </Style>
+    <!-- the traffic is a terminal: a line is as tall as its text -->
+    <Style Selector="ListBox#Traffic > ListBoxItem">
+      <Setter Property="Padding" Value="2,0" />
+      <Setter Property="MinHeight" Value="0" />
+      <Setter Property="Margin" Value="0" />
+    </Style>
   </Window.Styles>
 
   <TabControl Name="Tabs">
     <TabItem Header="Telnet">
       <DockPanel>
-        <Grid DockPanel.Dock="Top" ColumnDefinitions="*,Auto,Auto" Margin="8,6,8,4">
+        <Grid DockPanel.Dock="Top" ColumnDefinitions="*,Auto" Margin="8,6,8,4">
           <TextBlock Name="StateText" FontSize="11" Opacity="0.7" VerticalAlignment="Center" />
-          <TextBlock Grid.Column="1" Name="PausedText" Text="scrolling paused" FontSize="11"
-                     Margin="0,0,8,0" IsVisible="False" VerticalAlignment="Center" />
-          <Button Grid.Column="2" Name="ReconnectButton" Content="Reconnect" Click="OnReconnect" />
+          <Button Grid.Column="1" Name="ReconnectButton" Content="Reconnect" Click="OnReconnect" />
         </Grid>
         <StackPanel DockPanel.Dock="Bottom" Margin="8,4,8,8" Spacing="4">
           <WrapPanel Name="ButtonRow" />
@@ -29,8 +33,7 @@
           </DockPanel>
         </StackPanel>
         <ListBox Name="Traffic" FontFamily="monospace" FontSize="12" Margin="8,0"
-                 DoubleTapped="OnJumpToSpot"
-                 PointerEntered="OnTrafficEntered" PointerExited="OnTrafficExited">
+                 DoubleTapped="OnJumpToSpot">
           <ListBox.ContextMenu>
             <ContextMenu>
               <MenuItem Header="Jump to this spot" Click="OnJumpToSpot" />

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

@@ -17,7 +17,9 @@ namespace Nonemm.App.Windows;
 /// clicking a spot line puts the radio on it.
 public sealed partial class TelnetWindow : RefreshableWindow
 {
-    private const int LinesKept = 500;
+    /// A node can send a spot a second for many hours, so the window keeps
+    /// the last thousand lines and no more.
+    private const int LinesKept = 1000;
 
     private static IBrush SpotColour => Themes.Brush(Themes.Current.Multipliers);
 
@@ -29,7 +31,7 @@ public sealed partial class TelnetWindow : RefreshableWindow
     private readonly Action<Frequency, string> tune;
     private readonly List<string> history = [];
     private int recalled = -1;
-    private bool paused;
+    private bool scrollPending;
 
     public TelnetWindow(AppSession session, Action<Frequency, string> tune)
     {
@@ -141,7 +143,8 @@ public sealed partial class TelnetWindow : RefreshableWindow
     private void OnConnectionChanged(object? sender, bool connected) =>
         Dispatcher.UIThread.Post(Refresh);
 
-    /// `strong` marks the lines from a preferred spotter.
+    /// `strong` marks the lines from a preferred spotter. The view stays on the
+    /// newest line; a burst of lines is scrolled once, after the last of them.
     private void Show(string line, IBrush? colour, bool strong = false) => Dispatcher.UIThread.Post(() =>
     {
         while (Traffic.Items.Count >= LinesKept)
@@ -154,25 +157,16 @@ public sealed partial class TelnetWindow : RefreshableWindow
             Foreground = colour,
             FontWeight = strong ? FontWeight.Bold : FontWeight.Normal,
         });
-        if (!paused && Traffic.Items.Count > 0)
+        if (!scrollPending)
         {
-            Traffic.ScrollIntoView(Traffic.Items.Count - 1);
+            scrollPending = true;
+            Dispatcher.UIThread.Post(ScrollToNewest, DispatcherPriority.Background);
         }
-        Refresh();
     });
 
-    /// Scrolling stops while the pointer is over the traffic, so a line can be
-    /// read or copied while the node keeps sending.
-    private void OnTrafficEntered(object? sender, PointerEventArgs e)
+    private void ScrollToNewest()
     {
-        paused = true;
-        PausedText.IsVisible = true;
-    }
-
-    private void OnTrafficExited(object? sender, PointerEventArgs e)
-    {
-        paused = false;
-        PausedText.IsVisible = false;
+        scrollPending = false;
         if (Traffic.Items.Count > 0)
         {
             Traffic.ScrollIntoView(Traffic.Items.Count - 1);