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.Server/Game/GameLoopService.cs

@@ -167,6 +167,10 @@ internal sealed class GameLoopService(
                 RouteOpenSchool(setSpeed.PlayerId, new WorkerCommand.SetSpeed(setSpeed.SpeedIndex));
                 break;
 
+            case GameCommand.SkipEmpty skipEmpty:
+                RouteOpenSchool(skipEmpty.PlayerId, new WorkerCommand.SkipEmpty());
+                break;
+
             case GameCommand.ReloadSaves reload:
                 await HandleReloadAsync(reload).ConfigureAwait(false);
                 break;