Update wire protocol to version 7 and enhance presence management features

- Bumped the wire protocol version to 7, reflecting significant changes in the communication structure.
- Introduced a new presence message type for real-time occupancy updates, including node activity and individual presence states.
- Updated the API to include a directory endpoint for fetching short id→name mappings, improving client-side name resolution.
- Revised the map snapshot structure to be static, with people and current lessons now handled through the presence stream.
- Enhanced client-side handling of presence updates, including UI adjustments to display live occupancy and activity.
- Updated documentation to reflect the new protocol features and changes in presence management.
- Added tests to validate the new presence functionalities and ensure robust handling of real-time data.

src/HSchool.Simulation/School.cs

@@ -138,6 +138,18 @@ public sealed class School : IDisposable
 
     public bool IsCampusEmpty() => PresenceSystem.IsEmpty(this);
 
+    public SkipEmptyPeek PeekSkipEmpty()
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        if (Catalog is null || !IsCampusEmpty() || SchoolDay.InWorkWindow(Catalog, Clock.Time, SchoolWeekDays))
+        {
+            return SkipEmptyPeek.Refused;
+        }
+
+        var next = SchoolDay.NextWorkMorning(Catalog, Clock.Time, SchoolWeekDays, MaxSkipDays);
+        return next is null ? SkipEmptyPeek.Refused : new SkipEmptyPeek(true, next.Value);
+    }
+
     public SkipEmptyResult TrySkipEmpty()
     {
         ObjectDisposedException.ThrowIf(_disposed, this);
@@ -295,6 +307,11 @@ public enum SkipEmptyError
     NoMorning,
 }
 
+public readonly record struct SkipEmptyPeek(bool Allowed, DateTime? Time)
+{
+    public static SkipEmptyPeek Refused { get; } = new(false, null);
+}
+
 public readonly record struct SkipEmptyResult(SkipEmptyError Error, DateTime? Time, bool PeopleChanged)
 {
     public bool Succeeded => Error == SkipEmptyError.None;