[Replay] Show the history sidebar in replay tabs

Add the Game History dock to the left of replay tabs, wire it to the replay timeline, and register it with the View menu and layout reset.

cockatrice/src/interface/widgets/replay/replay_manager.h

@@ -66,6 +66,16 @@ public:
         return replayTimeline;
     }
 
+    /**
+     * @brief Index of the last event the game state has processed.
+     *
+     * @return The event index, or -1 while no event has been replayed yet
+     */
+    [[nodiscard]] int getLastProcessedEventIndex() const
+    {
+        return currentEvent - 1;
+    }
+
     void setTimeScaleFactor(qreal _timeScaleFactor);
     void setSkipEmptySections(bool value);