Write what N1MM needs before it will open a log

Checked by opening a log this program wrote in N1MM 1.0.11031. Three things it
rejected:

- a log naming a contest with no row in the Contest table throws "No current
  row" in Contest.FromRow, so the definition row is written whenever a contest
  is opened;
- an empty overlay category is answered with "Invalid Overlay Category:", so an
  entry with no overlay now says "N/A", and the dialog offers N1MM's list;
- the sent exchange omits the report, which is what N1MM's own contest dialog
  asks for.

With those three fixed N1MM opens the log and shows the contacts.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/Nonemm.Contests/Rules/ArrlDx.cs

@@ -35,9 +35,7 @@ public sealed class ArrlDx : Contest
     public IReadOnlyList<ModeCategory> Modes => [mode];
 
     public string SentExchangeFor(StationInfo me) =>
-        IsNorthAmericanHome(me)
-            ? $"{DefaultReport()} {StateOrProvince(me)}"
-            : $"{DefaultReport()} {me.Power}";
+        IsNorthAmericanHome(me) ? StateOrProvince(me) : me.Power;
 
     /// Only contacts across the W/VE line count, so a DX station working DX or
     /// a W station working W scores nothing.
@@ -88,5 +86,4 @@ public sealed class ArrlDx : Contest
 
     private string ModeLabel() => mode == ModeCategory.Cw ? "CW" : "SSB";
 
-    private string DefaultReport() => mode == ModeCategory.Cw ? "599" : "59";
 }

src/Nonemm.Contests/Rules/CqWorldWide.cs

@@ -31,8 +31,9 @@ public sealed class CqWorldWide : Contest
 
     public IReadOnlyList<ModeCategory> Modes => [mode];
 
-    public string SentExchangeFor(StationInfo me) =>
-        $"{DefaultReport()} {me.CqZone}";
+    /// The report is fixed for the whole contest, so the sent exchange is the
+    /// zone alone, which is also what N1MM stores.
+    public string SentExchangeFor(StationInfo me) => me.CqZone.ToString();
 
     public int PointsFor(QsoContext qso)
     {
@@ -83,5 +84,4 @@ public sealed class CqWorldWide : Contest
 
     private string ModeLabel() => mode == ModeCategory.Cw ? "CW" : "SSB";
 
-    private string DefaultReport() => mode == ModeCategory.Cw ? "599" : "59";
 }

src/Nonemm.Contests/Rules/CqWpx.cs

@@ -40,7 +40,9 @@ public sealed class CqWpx : Contest
 
     public IReadOnlyList<ModeCategory> Modes => [mode];
 
-    public string SentExchangeFor(StationInfo me) => DefaultReport();
+    /// The serial number is generated per contact, so the stored exchange is
+    /// the number the contest starts at.
+    public string SentExchangeFor(StationInfo me) => "001";
 
     public int PointsFor(QsoContext qso)
     {
@@ -89,5 +91,4 @@ public sealed class CqWpx : Contest
         _ => "RTTY",
     };
 
-    private string DefaultReport() => mode == ModeCategory.Phone ? "59" : "599";
 }

src/Nonemm.Contests/Rules/GeneralLogging.cs

@@ -27,7 +27,7 @@ public sealed class GeneralLogging : Contest
 
     public IReadOnlyList<ModeCategory> Modes => [];
 
-    public string SentExchangeFor(StationInfo me) => "599";
+    public string SentExchangeFor(StationInfo me) => "";
 
     public int PointsFor(QsoContext qso) => 0;
 

src/Nonemm.Contests/Rules/IaruHf.cs

@@ -26,7 +26,7 @@ public sealed class IaruHf : Contest
 
     public IReadOnlyList<ModeCategory> Modes => [ModeCategory.Cw, ModeCategory.Phone];
 
-    public string SentExchangeFor(StationInfo me) => $"599 {me.ItuZone}";
+    public string SentExchangeFor(StationInfo me) => me.ItuZone.ToString();
 
     public int PointsFor(QsoContext qso)
     {

src/Nonemm.Contests/Rules/RttyRoundup.cs

@@ -28,7 +28,7 @@ public sealed class RttyRoundup : Contest
     public IReadOnlyList<ModeCategory> Modes => [ModeCategory.Digital];
 
     public string SentExchangeFor(StationInfo me) =>
-        me.State.Length > 0 ? $"599 {me.State}" : "599";
+        me.State.Length > 0 ? me.State : "001";
 
     public int PointsFor(QsoContext qso) => 1;