Show talk-circle partners and topic on the location panel and Now tab.

The frame and card share member ids; the client builds the sentence from the directory and locale.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/HSchool.Simulation/PresenceSystem.cs

@@ -621,3 +621,6 @@ public sealed record PresenceSnapshot(
     string? GoalId = null,
     float GoalWeight = 0f,
     string? GoalAction = null);
+
+/// <summary>Ids of an active talk circle. Names are resolved by the client, not here.</summary>
+public sealed record TalkCirclePresence(string TopicId, IReadOnlyList<string> MemberIds);