[Game] Prevent spectator duplication when replaying joined events (#7248)

* [Game] Prevent spectator duplication when replaying joined events

The spectator branch of eventJoin emitted spectatorJoined unconditionally
even when the spectator was already present (e.g. replayed during a rewind).
Guard it like the player branch and eventGameStateChanged, and make
PlayerListWidget::addPlayer idempotent as defense in depth.

* In resetChatAndPhase() (the rewound() handler), also clear all spectators from both PlayerManager and PlayerListWidget before the replay rebuilds from event 0. The forward replay then re-adds exactly the spectators whose join events fall within the new time range via eventGameStateChanged/eventJoin.

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/game_graphics/player/player_list_widget.cpp

@@ -92,6 +92,11 @@ void PlayerListWidget::retranslateUi()
 
 void PlayerListWidget::addPlayer(const ServerInfo_PlayerProperties &player)
 {
+    if (players.contains(player.player_id())) {
+        updatePlayerProperties(player);
+        return;
+    }
+
     QTreeWidgetItem *newPlayer = new PlayerListTWI;
     players.insert(player.player_id(), newPlayer);
     updatePlayerProperties(player);
@@ -176,6 +181,17 @@ void PlayerListWidget::removePlayer(int playerId)
     delete takeTopLevelItem(indexOfTopLevelItem(player));
 }
 
+void PlayerListWidget::clearSpectators()
+{
+    const QList<int> playerIds = players.keys();
+    for (int playerId : playerIds) {
+        QTreeWidgetItem *player = players.value(playerId, 0);
+        if (player && !player->data(1, Qt::UserRole).toBool()) {
+            removePlayer(playerId);
+        }
+    }
+}
+
 void PlayerListWidget::setActivePlayer(int playerId)
 {
     QMapIterator<int, QTreeWidgetItem *> i(players);

cockatrice/src/game_graphics/player/player_list_widget.h

@@ -66,6 +66,7 @@ public slots:
     void addPlayer(const ServerInfo_PlayerProperties &player);
     void removePlayer(int playerId);
     void updatePlayerProperties(const ServerInfo_PlayerProperties &prop, int playerId = -1);
+    void clearSpectators();
 };
 
 #endif