Wipe on Alt+W as well as put the boxes back

Alt+W only put the boxes back, so wiping needed Ctrl+W or the button.
It now goes both ways, the way N1MM's Wipe button does: with something in
the boxes it clears them, and pressed again on empty boxes it puts back
what it cleared.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015NZkFxHde1iifAQemFTHxf

tests/Nonemm.Session.Tests/OperatingPositionTests.cs

@@ -649,7 +649,23 @@ public class OperatingPositionTests
     public void EmptyBoxesGiveNoProblem() =>
         Assert.Null(Session().EntryProblem());
 
-    /// N1MM's Alt+W: a wipe keeps what was in the boxes and Alt+W puts it back.
+    /// N1MM's Alt+W goes both ways: it wipes the boxes, and pressed again on
+    /// empty boxes it puts back what it wiped.
+    [Fact]
+    public void AltWWipesAndThenPutsTheBoxesBack()
+    {
+        OperatingPosition session = Session();
+        Type(session, "JA1XYZ", "25");
+
+        session.WipeOrRestore();
+        Assert.Equal("", session.Entry.Call);
+
+        session.WipeOrRestore();
+        Assert.Equal("JA1XYZ", session.Entry.Call);
+        Assert.Equal("25", session.Entry.ValueOf(ExchangeSlot.Zone));
+    }
+
+    /// A wipe keeps what was in the boxes and Alt+W puts it back.
     [Fact]
     public void WhatAWipeClearedComesBack()
     {