[Client] Let moderators set the turn order

The server accepts SET_PLAYER_ORDER from the host or a moderator, but the
client hid the action from everyone except the host, making the moderator
branch unreachable. Visibility and the handler now share canSetTurnOrder().

cockatrice/src/interface/widgets/tabs/tab_game.cpp

@@ -634,7 +634,7 @@ void TabGame::actConcede()
 
 void TabGame::actTurnOrder()
 {
-    if (!game->isHost() || game->getGameMetaInfo()->started()) {
+    if (!canSetTurnOrder()) {
         return;
     }
 
@@ -668,17 +668,35 @@ void TabGame::actTurnOrder()
     game->getGameEventHandler()->handleSetPlayerOrder(dlg.order(), dlg.isRandomizeRequested());
 }
 
+/**
+ * Whether the local user may change the seating order: only while the game has
+ * not started, and only as the host or a moderator - the server allows both
+ * (Server_AbstractParticipant::cmdSetPlayerOrder).
+ */
+bool TabGame::canSetTurnOrder() const
+{
+    if (game->getGameMetaInfo()->started()) {
+        return false;
+    }
+    if (game->isHost()) {
+        return true;
+    }
+    const ServerInfo_User *userInfo = tabSupervisor->getUserInfo();
+    return userInfo != nullptr && (userInfo->user_level() & ServerInfo_User::IsModerator);
+}
+
 /**
  * Shows the turn order action only when it can actually change anything: the
- * player must be host and the game must not have started yet. Called whenever
+ * player must be allowed to set the order and the game must not have started.
- * either condition may have changed (game start/stop, host change).
+ * Called whenever either condition may have changed (game start/stop, host
+ * change).
  */
 void TabGame::updateTurnOrderAction()
 {
     if (aTurnOrder == nullptr) {
         return;
     }
-    aTurnOrder->setVisible(game->isHost() && !game->getGameMetaInfo()->started());
+    aTurnOrder->setVisible(canSetTurnOrder());
 }
 
 /**

cockatrice/src/interface/widgets/tabs/tab_game.h

@@ -130,6 +130,7 @@ private:
 
     PlayerLogic *setActivePlayer(int id);
     void setActivePhase(int phase);
+    bool canSetTurnOrder() const;
     void createMenuItems();
     void createReplayMenuItems();
     void createViewMenuItems();