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/Messages.cs

@@ -0,0 +1,22 @@
+namespace Nonemm.App;
+
+/// The function key messages. The text uses N1MM's macro names so a message
+/// file written for either program means the same thing.
+public static class Messages
+{
+    public static readonly IReadOnlyList<(string Key, string Label, string Text)> Defaults =
+    [
+        ("F1", "CQ", "CQ TEST {MYCALL} {MYCALL}"),
+        ("F2", "Exch", "{SENTRST} {EXCH}"),
+        ("F3", "TU", "TU {MYCALL}"),
+        ("F4", "MyCall", "{MYCALL}"),
+        ("F5", "HisCall", "{CALL}"),
+        ("F6", "Repeat", "{EXCH} {EXCH}"),
+        ("F7", "?", "?"),
+        ("F8", "Agn", "AGN"),
+        ("F9", "Nr?", "NR?"),
+        ("F10", "Call?", "CALL?"),
+        ("F11", "Spot", ""),
+        ("F12", "Wipe", ""),
+    ];
+}