Show the other computers, and apply the ten-minute rule

Three pieces on top of the link:

**The network status window**, on the entry window's Window menu. A row
per station, this computer included the way N1MM shows it: number,
address, operator, band, mode, run, transmit, pass frequency, the last
message type, how long ago it arrived, the counts each way and the echo
round trip. A station that broadcast the wrong version is named under the
table in red — that is the one fault where everything looks connected
and nothing arrives. The box at the bottom sends a line of chat, and
Echo asks every station whether it is there.

**Where this station is** goes out once a second when it has changed.
The frequency, the mode and run have a dozen places they can change from
— the radio moving, a band button, a QSY typed into the callsign box —
so it is read and compared rather than announced from each of them.

**The ten-minute rule.** `BandChangeRules` already counted changes and
the stay on a band, and the entry window already showed the countdown,
but only a user-defined contest carried a rule, so every built-in
contest allowed anything. `ForCategory` gives a multi-operator entry
with one or two transmitters a ten-minute stay, which is N1MM's fallback
in `ContestInstance.BandChangeTimerDuration` for every contest that does
not name its own. Its per-contest table is a few hundred cases in a
decompiled hash switch and is not repeated.

Config ▸ Edit Networked-Computer Names now covers both networks: the
12060 broadcast to other programs and the 12070 link, with the station
number, the port, the version to claim and stations named by address for
a network where a broadcast does not reach.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PdAYHcdRktqKry7nk414TU

src/Nonemm.App/Windows/NetworkStatusWindow.axaml

@@ -0,0 +1,23 @@
+<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.NetworkStatusWindow"
+        Title="Network status" Width="820" Height="320">
+  <DockPanel Margin="8">
+    <StackPanel DockPanel.Dock="Bottom" Spacing="6" Margin="0,8,0,0">
+      <StackPanel Orientation="Horizontal" Spacing="6">
+        <TextBox Name="TalkBox" Width="420" PlaceholderText="a line to the other operators" />
+        <Button Content="Send" Click="OnTalk" IsDefault="True" />
+        <Button Content="Echo" Click="OnEcho" />
+        <Button Name="LinkButton" Content="Setup…" Click="OnSetup" />
+      </StackPanel>
+      <TextBlock Name="StateText" FontSize="11" Opacity="0.75" TextWrapping="Wrap" />
+    </StackPanel>
+    <ScrollViewer>
+      <StackPanel Spacing="6">
+        <Grid Name="Table" />
+        <TextBlock Name="TalkText" FontFamily="monospace" FontSize="11" TextWrapping="Wrap" />
+      </StackPanel>
+    </ScrollViewer>
+  </DockPanel>
+</local:RefreshableWindow>