add quick add entry.

API/ROLAC.API/Hubs/OfferingEntryHub.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.SignalR;
+
+namespace ROLAC.API.Hubs;
+
+/// <summary>
+/// Real-time hub backing the mobile Sunday offering-entry page. Anonymous
+/// (no [Authorize]) so volunteers can enter givings on their phones without
+/// logging in. Clients join a group named after the session date (yyyy-MM-dd);
+/// when a line is appended, the controller broadcasts "LineAdded" to that
+/// group so every phone and the desktop Sunday Offering Entry page updating
+/// the same date see the new line instantly. The hub itself holds no business
+/// logic — broadcasting is done from the controller via IHubContext.
+/// </summary>
+public class OfferingEntryHub : Hub
+{
+    public Task JoinDate(string date)
+        => Groups.AddToGroupAsync(Context.ConnectionId, date);
+
+    public Task LeaveDate(string date)
+        => Groups.RemoveFromGroupAsync(Context.ConnectionId, date);
+}