Take a QTC header that is only a series number as ten lines

An operator copying a header off the air often types the series number and
nothing else. That read as a header the program could not parse, so the box
went yellow and Close refused to log the series.

N1MM fills the count in: "If he only types the batch number without the
forward slash and count, the program will assume the count is 10."

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0157i7PiZyqBkquxS9A6FTdQ

tests/Nonemm.Session.Tests/QtcTrafficTests.cs

@@ -314,9 +314,21 @@ public class QtcTrafficTests
         Assert.Equal(10, count);
     }
 
+    /// N1MM fills in the count when the operator types the series number
+    /// alone, because ten is the usual series.
+    [Theory]
+    [InlineData("87")]
+    [InlineData("QTC 87")]
+    public void ASeriesNumberOnItsOwnMeansTenLines(string text)
+    {
+        (int series, int count) = Assert.IsType<(int, int)>(QtcTraffic.ReadHeader(text));
+
+        Assert.Equal(87, series);
+        Assert.Equal(10, count);
+    }
+
     [Theory]
     [InlineData("")]
-    [InlineData("87")]
     [InlineData("87/11")]
     [InlineData("abc/10")]
     public void AHeaderThatIsNotOneReadsAsNothing(string text) =>