Black box: the queries of the user's train worked out once a read, lights as the driver checks them

- The stations, the signals passed, the horn points, the couplings, the
  consists and the timetable progress of the user's train are kept until
  a read adds something; the views asked for them every frame, which on
  a long session with many trains took the window down. A read that adds
  nothing no longer counts as a change.
- The lights are checked against the lamps the vehicles at the ends have
  (written by the simulator from now on), as its driver checks them: Pc 1
  without the upper headlight, with the auxiliary lamps, Pc 5 with the
  rear-end signals. Only while the user drives: the autopilot's lights
  are its own.
- A train off the platform counts at both ends: its head past the stop
  point as well as its tail before the platform's end.
- A recording without the couplings keeps the timetable for any vehicle
  of the user.
- A signal passed at danger is ringed on the map only once it was.
- In the tapes window a black box opens on a click or Enter, not when
  the arrow keys go over it.
- The viewer's screenshot of a window not laid out saves nothing and
  still closes.

Eu07.BlackBox/TimetableProgress.cs

@@ -66,7 +66,10 @@ public sealed record StationProgress(
         recording.TimetableAt(t) is { } timetable ? Of(recording, timetable) : Array.Empty<StationProgress>();
 
     /// <summary>The rows of a timetable of the recording, each with what the train did there.</summary>
-    public static IReadOnlyList<StationProgress> Of(Recording recording, Timetable timetable)
+    public static IReadOnlyList<StationProgress> Of(Recording recording, Timetable timetable) =>
+        recording.Memo((typeof(StationProgress), timetable), () => Work(recording, timetable));
+
+    private static IReadOnlyList<StationProgress> Work(Recording recording, Timetable timetable)
     {
         // The records of this train: from its timetable on, until another one is written. A train given its next
         // timetable may come to the first station of it at once, and a recording made before the simulator wrote the