Add AVA2-style display options (effect level, trees, clouds)

Client-only port of ENABLE_GRAPHIC_ON_OFF / HIDE_OBJECTS: five effect
levels toggle attached actor effects via Active/Deactive, tree and cloud
parts use background.SetVisiblePart, plus shortcuts for the original
name and damage options. mt_display window, mt_display.cfg, port.display
test, docs/AVA2-DISPLAY.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/port/UserInterface/InstanceBase.cpp

@@ -4,6 +4,7 @@
 #include "PythonNonPlayer.h"
 #include "PythonPlayer.h"
 #include "PythonCharacterManager.h"
+#include "PythonSystem.h"
 #include "AbstractPlayer.h"
 #include "AbstractApplication.h"
 #include "Packet.h"
@@ -1868,6 +1869,7 @@ void CInstanceBase::Update()
 {
 	++ms_dwUpdateCounter;	
 
+	__UpdateEffectShown();
 	StateProcess();
 	m_GraphicThingInstance.PhysicsProcess();
 	m_GraphicThingInstance.RotationProcess();
@@ -2454,6 +2456,25 @@ bool CInstanceBase::__IsInViewFrustum()
 	return m_GraphicThingInstance.isShow();
 }
 
+// PORT: AVA2 ENABLE_GRAPHIC_ON_OFF effect level, applied to attached effects (skills, buffs, refine glow).
+void CInstanceBase::__UpdateEffectShown()
+{
+	const int iLevel = CPythonSystem::Instance().GetEffectLevel();
+	bool isShown = true;
+	if (iLevel == 4)
+		isShown = false;
+	else if (iLevel != 0 && !__IsMainInstance())
+	{
+		if (iLevel == 1)
+			isShown = IsEnemy() || IsStone();
+		else if (iLevel == 2)
+			isShown = IsPC();
+		else
+			isShown = false;
+	}
+	m_GraphicThingInstance.SetAttachingEffectShown(isShown);
+}
+
 bool CInstanceBase::__CanRender()
 {
 	if (!__IsInViewFrustum())