Write LOCATION to Cabrillo, and give CQ WW M/2 eight band changes an hour

CQ WW lists LOCATION as required, and the export never wrote it. It now
carries the ARRL section, state or province, or DX.

CQ WW M/2 has no stay on a band: it may make eight band changes in a clock
hour. It was getting the ten-minute stay that M/S has.

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

src/Nonemm.Formats/Cabrillo/CabrilloHeader.cs

@@ -27,6 +27,10 @@ public sealed record CabrilloHeader
 
     public string TimeCategory { get; init; } = "";
 
+    /// The state, province or ARRL section of a station in the US or Canada,
+    /// and `DX` for everywhere else, which is what CQ WW asks for.
+    public string Location { get; init; } = "";
+
     public long ClaimedScore { get; init; }
 
     public string Club { get; init; } = "";

src/Nonemm.Formats/Cabrillo/CabrilloWriter.cs

@@ -35,6 +35,7 @@ public sealed class CabrilloWriter
         Line(text, "CATEGORY-TRANSMITTER", header.TransmitterCategory);
         Line(text, "CATEGORY-OVERLAY", header.OverlayCategory);
         Line(text, "CATEGORY-TIME", header.TimeCategory);
+        Line(text, "LOCATION", header.Location);
         text.Append(CultureInfo.InvariantCulture, $"CLAIMED-SCORE: {header.ClaimedScore}\r\n");
         Line(text, "CLUB", header.Club);
         Line(text, "NAME", header.Name);