switch to using own event system

src/balancing/ArenaWidget.h

@@ -14,19 +14,16 @@ class ArenaWidget : public QFrame
     Q_OBJECT
 
 public:
-    explicit ArenaWidget(const std::string& arenaName, QWidget* parent = nullptr);
+    ArenaWidget(int arenaIndex, const std::string& arenaName, QWidget* parent = nullptr);
 
     void updateStatus(const ArenaStatus& status);
     void startSimulation();
     void resetToGrey();
 
-signals:
-    void startRequested();
-    void inspectRequested();
-
 private:
     void buildLayout(const std::string& arenaName);
 
+    int m_arenaIndex;
     QLabel* m_titleLabel;
     QLabel* m_team1Header;
     QLabel* m_team2Header;