Fix multiple memory leaks and stale pooled allocations

* Fix Vec3/AABB pool reset logic

  * resetPool()/clearPool() now reset poolPointer to 0
  * Prevents endless pool growth, invalid temporary references,
    and increasing memory usage
  * Resolves the leaderboard-related crash mentioned in
    Windows64_Minecraft.cpp

* Properly free old screens in Minecraft::setScreen()

  * Added virtual destructor to Screen
  * Screen destructor now cleans up GuiParticles and Buttons
  * Previous screen is now deleted after screen transitions
  * Screen::init() now clears old buttons/particles before re-init

* Fix GuiParticles memory leak

  * Removed GuiParticle instances are now deleted in tick()
  * Added GuiParticles destructor to free remaining particles

Minecraft.Client/GuiParticles.cpp

@@ -8,6 +8,15 @@ GuiParticles::GuiParticles(Minecraft *mc)
 	this->mc = mc;
 }
 
+GuiParticles::~GuiParticles()
+{
+	for (GuiParticle *gp : particles)
+	{
+		delete gp;
+	}
+	particles.clear();
+}
+
 void GuiParticles::tick()
 {
     for (unsigned int i = 0; i < particles.size(); i++)
@@ -19,6 +28,7 @@ void GuiParticles::tick()
 
         if (gp->removed)
 		{
+            delete gp;
             particles.erase(particles.begin()+i);
 			i--;
         }

Minecraft.Client/GuiParticles.h

@@ -13,6 +13,7 @@ private:
 
 public:
 	GuiParticles(Minecraft *mc);
+    ~GuiParticles();
     void tick();
     void add(GuiParticle *guiParticle);
     void render(float a);

Minecraft.Client/Minecraft.cpp

@@ -504,9 +504,10 @@ LevelStorageSource *Minecraft::getLevelSource()
 
 void Minecraft::setScreen(Screen *screen)
 {
-	if (this->screen != nullptr)
+	Screen *oldScreen = this->screen;
+	if (oldScreen != nullptr)
 	{
-		this->screen->removed();
+		oldScreen->removed();
 	}
 
 #ifdef _WINDOWS64

Minecraft.Client/Screen.cpp

@@ -23,6 +23,18 @@ Screen::Screen()	// 4J added
 	clickedButton = nullptr;
 }
 
+Screen::~Screen()
+{
+	delete particles;
+	particles = nullptr;
+
+	for (Button *button : buttons)
+	{
+		delete button;
+	}
+	buttons.clear();
+}
+
 void Screen::render(int xm, int ym, float a)
 {
 	for (Button* button : buttons)

Minecraft.Client/Screen.h

@@ -22,6 +22,7 @@ public:
 	GuiParticles *particles;
 
 	Screen();		// 4J added
+    virtual ~Screen();
     virtual void render(int xm, int ym, float a);
 protected:
 	virtual void keyPressed(wchar_t eventCharacter, int eventKey);

Minecraft.World/AABB.cpp

@@ -54,10 +54,16 @@ AABB *AABB::newPermanent(double x0, double y0, double z0, double x1, double y1,
 
 void AABB::clearPool()
 {
+	ThreadStorage *tls = static_cast<ThreadStorage *>(TlsGetValue(tlsIdx));
+	if (tls != nullptr)
+	{
+		tls->poolPointer = 0;
+	}
 }
 
 void AABB::resetPool()
 {
+	clearPool();
 }
 
 AABB *AABB::newTemp(double x0, double y0, double z0, double x1, double y1, double z1)

Minecraft.World/Vec3.cpp

@@ -47,10 +47,16 @@ Vec3 *Vec3::newPermanent(double x, double y, double z)
 
 void Vec3::clearPool()
 {
+	ThreadStorage *tls = static_cast<ThreadStorage *>(TlsGetValue(tlsIdx));
+	if (tls != nullptr)
+	{
+		tls->poolPointer = 0;
+	}
 }
 
 void Vec3::resetPool()
 {
+	clearPool();
 }
 
 Vec3 *Vec3::newTemp(double x, double y, double z)