Add the Avalonia application and the station network

The entry window types contacts and colours them as they are typed; the log,
check, bandmap, score and packet windows read the same session. Contacts are
shared with the other stations of a multi-operator entry in N1MM's contact
message, so an N1MM station on the same network sees them too.

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

src/Nonemm.Session/CheckCandidate.cs

@@ -0,0 +1,25 @@
+using Nonemm.Contests;
+using Nonemm.Core.Calls;
+
+namespace Nonemm.Session;
+
+/// One callsign the check window offers, with what the log says about it so it
+/// is coloured the same as everywhere else.
+public sealed record CheckCandidate(string Call, PartialMatchQuality Quality, Verdict? Verdict);
+
+/// Where a column of candidates came from. They stay apart because they answer
+/// different questions: the log is what this station copied itself, the
+/// database is a guess about the whole world, and the bandmap is somebody
+/// else's claim.
+public enum CheckSource
+{
+    Log,
+    Database,
+    Bandmap,
+}
+
+/// One column of the check window.
+public sealed record CheckColumn(
+    CheckSource Source,
+    int Held,
+    IReadOnlyList<CheckCandidate> Candidates);

src/Nonemm.Session/CheckWindowSources.cs

@@ -0,0 +1,86 @@
+using Nonemm.Contests;
+using Nonemm.Core;
+using Nonemm.Core.Calls;
+using Nonemm.Spotting;
+
+namespace Nonemm.Session;
+
+/// Answers what the callsign being typed could be, a column per source.
+public sealed class CheckWindowSources
+{
+    private readonly LoggingSession session;
+    private readonly CallDatabase database;
+    private readonly Bandmap bandmap;
+
+    public CheckWindowSources(LoggingSession session, CallDatabase database, Bandmap bandmap)
+    {
+        this.session = session;
+        this.database = database;
+        this.bandmap = bandmap;
+    }
+
+    public IReadOnlyList<CheckColumn> Columns(string typed, int limit = 24)
+    {
+        string query = typed.Trim().ToUpperInvariant();
+        return
+        [
+            Column(CheckSource.Log, LoggedCalls(), query, limit),
+            new CheckColumn(
+                CheckSource.Database,
+                database.Count,
+                query.Length < PartialMatching.ShortestUsefulQuery
+                    ? []
+                    : database.Matches(query, limit).Select(Judged).ToList()),
+            Column(CheckSource.Bandmap, SpottedCalls(), query, limit),
+        ];
+    }
+
+    private CheckColumn Column(
+        CheckSource source,
+        IReadOnlyList<string> calls,
+        string query,
+        int limit)
+    {
+        if (query.Length < PartialMatching.ShortestUsefulQuery)
+        {
+            return new CheckColumn(source, calls.Count, []);
+        }
+        List<CheckCandidate> found = [];
+        foreach (string call in calls)
+        {
+            PartialMatchQuality? quality = PartialMatching.Judge(query, call);
+            if (quality is not null)
+            {
+                found.Add(Judged(new PartialMatch(call, quality.Value)));
+            }
+        }
+        return new CheckColumn(
+            source,
+            calls.Count,
+            found.OrderBy(c => c.Quality).ThenBy(c => c.Call, StringComparer.Ordinal).Take(limit).ToList());
+    }
+
+    private CheckCandidate Judged(PartialMatch match) =>
+        new(match.Call, match.Quality, VerdictFor(match.Call));
+
+    /// What logging this call on the current band and mode would do.
+    private Verdict? VerdictFor(string call)
+    {
+        Qso candidate = new()
+        {
+            Id = "",
+            TimestampUtc = DateTime.UtcNow,
+            Call = Callsign.Parse(call),
+            Frequency = session.Frequency,
+            Mode = session.Mode,
+            ContestName = session.Contest.Name,
+        };
+        return session.Log.Judge(candidate);
+    }
+
+    private IReadOnlyList<string> LoggedCalls() =>
+        session.Log.Qsos.Select(q => q.Call.Text).Distinct(StringComparer.Ordinal).ToList();
+
+    private IReadOnlyList<string> SpottedCalls() =>
+        bandmap.All().Select(s => s.Call.Text).Distinct(StringComparer.Ordinal).ToList();
+}

src/Nonemm.Session/Nonemm.Session.csproj

@@ -5,6 +5,7 @@
     <ProjectReference Include="..\Nonemm.Contests\Nonemm.Contests.csproj" />
     <ProjectReference Include="..\Nonemm.Storage\Nonemm.Storage.csproj" />
     <ProjectReference Include="..\Nonemm.Formats\Nonemm.Formats.csproj" />
+    <ProjectReference Include="..\Nonemm.Spotting\Nonemm.Spotting.csproj" />
   </ItemGroup>
 
   <PropertyGroup>