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>

tests/Nonemm.Session.Tests/FakeLogStore.cs

@@ -10,6 +10,12 @@ public sealed class FakeLogStore : LogStore
 {
     private readonly List<Qso> qsos = [];
     private readonly List<ContestInstance> contests = [];
+    private readonly List<ContestDefinition> definitions = [];
+
+    public IReadOnlyList<ContestDefinition> Definitions => definitions;
+
+    public void SaveContestDefinition(ContestDefinition definition) =>
+        definitions.Add(definition);
 
     public IReadOnlyList<ContestInstance> Contests() => contests;