Reconcile tax counter visibility ownership and harden tax log formatting

- Make AbstractCounter::setActive() the sole owner of counter visibility; document the contract.
  - Drop the redundant setVisible() from CommandZone::rearrangeTaxCounters(); it now only lays out by isActive().
  - Format tax log lines with a single atomic 4-arg arg() instead of mixing string and int overloads.

cockatrice/src/game_graphics/board/abstract_counter.h

@@ -113,7 +113,13 @@ public:
 
     /**
      * @brief Sets the active state of this counter.
-     * When inactive, the counter is hidden via setVisible(false).
+     *
+     * This is the sole owner of the counter's own visibility flag: active maps directly to
+     * setVisible(_active). For counters nested in another item (e.g. tax counters parented to
+     * the command zone), Qt AND-s this flag with the parent's visibility, so an active counter
+     * inside a hidden zone still does not render. Container layout code must therefore not set
+     * visibility itself; it only positions counters and may read isActive().
+     *
      * @param _active True to show and enable the counter, false to hide it
      */
     virtual void setActive(bool _active);

cockatrice/src/game_graphics/log/message_log_widget.cpp

@@ -680,12 +680,15 @@ void MessageLogWidget::logSetCounter(PlayerLogic *player, QString counterName, i
         QString playerName = sanitizeHtml(player->getPlayerInfo()->getName());
         QString valueStr = QString("<font class=\"blue\">%1</font>").arg(value);
         int delta = value - oldValue;
+        QString deltaStr = QString::number(delta);
         QString counterDisplayName = TranslateCounterName::getDisplayName(counterName);
         QString taxLabel = QString("<font class=\"blue\">%1</font>").arg(sanitizeHtml(counterDisplayName));
         if (value > oldValue) {
-            appendHtmlServerMessage(tr("%1 increases %2 to %3 (+%4).").arg(playerName, taxLabel, valueStr).arg(delta));
+            // delta > 0 here; the format string supplies the leading '+'
+            appendHtmlServerMessage(tr("%1 increases %2 to %3 (+%4).").arg(playerName, taxLabel, valueStr, deltaStr));
         } else {
-            appendHtmlServerMessage(tr("%1 decreases %2 to %3 (%4).").arg(playerName, taxLabel, valueStr).arg(delta));
+            // delta < 0 here; deltaStr already carries the '-' sign
+            appendHtmlServerMessage(tr("%1 decreases %2 to %3 (%4).").arg(playerName, taxLabel, valueStr, deltaStr));
         }
         return;
     }

cockatrice/src/game_graphics/zones/command_zone.cpp

@@ -150,7 +150,6 @@ void CommandZone::registerTaxCounter(AbstractCounter *counter)
 
 void CommandZone::rearrangeTaxCounters()
 {
-    bool commandZoneVisible = isVisible();
     int activeTaxCounterCount = 0;
 
     for (AbstractCounter *ctr : taxCounters) {
@@ -158,9 +157,11 @@ void CommandZone::rearrangeTaxCounters()
                   activeTaxCounterCount * (TaxCounterSizes::TAX_COUNTER_SIZE + TaxCounterSizes::TAX_COUNTER_MARGIN);
         ctr->setPos(TaxCounterSizes::TAX_COUNTER_MARGIN, y);
         ctr->setZValue(ZValues::TAX_COUNTERS);
-        bool visible = commandZoneVisible && ctr->isActive();
+        // Visibility is owned solely by AbstractCounter::setActive() (the counter's own flag),
-        ctr->setVisible(visible);
+        // which Qt AND-s with this CommandZone's visibility via child-visibility propagation
-        if (visible) {
+        // (tax counters are graphics children of the zone). This function only handles layout,
+        // so it stacks and measures by isActive() alone.
+        if (ctr->isActive()) {
             ++activeTaxCounterCount;
         }
     }