feat(npc): 添加NPC交互高亮效果及复合纹理支持

实现NPC交互时的绿色高亮效果，通过InteractionHighlightSprite类实现
重构NpcAnimation支持复合纹理渲染，优化高亮效果的性能
添加ShaderManager获取所有加载Shader的方法，优化渲染器uniform更新逻辑

Game/src/npc/NpcObject.cpp

@@ -42,10 +42,13 @@ bool NpcObject::Construction(int npcId) {
   worldPosition_ = CharacterWorldPosition();
   config_.reset();
   animation_ = nullptr;
+  interactionHighlight_ = nullptr;
   nameOutlineLabels_.fill(nullptr);
   nameLabel_ = nullptr;
   interactable_ = true;
   interacting_ = false;
+  interactionHighlighted_ = false;
+  syncedHighlightCompositeVersion_ = 0;
 
   auto config = npc::loadNpcConfig(npcId);
   if (!config) {
@@ -68,11 +71,13 @@ bool NpcObject::Construction(int npcId) {
   config_ = *config;
   npcId_ = npcId;
   animation_ = animation;
+  EnsureInteractionHighlight();
   AddChild(animation_);
   EnsureNameLabel();
 
   SetWorldPosition({});
   SetDirection(1);
+  SetInteractionHighlighted(false);
   RefreshNameLabel();
   SDL_Log("NpcObject: npc %d construction complete", npcId_);
   return true;
@@ -84,6 +89,7 @@ void NpcObject::SetDirection(int direction) {
     animation_->SetDirection(direction_);
   }
   RefreshNameLabel();
+  SyncInteractionHighlight();
 }
 
 void NpcObject::SetNpcPosition(const Vec2& pos) {
@@ -108,6 +114,19 @@ void NpcObject::SetInteractable(bool interactable) {
   }
 }
 
+void NpcObject::SetInteractionHighlighted(bool highlighted) {
+  if (interactionHighlighted_ == highlighted) {
+    SyncInteractionHighlight();
+    return;
+  }
+
+  interactionHighlighted_ = highlighted;
+  if (!interactionHighlighted_) {
+    syncedHighlightCompositeVersion_ = 0;
+  }
+  SyncInteractionHighlight();
+}
+
 void NpcObject::BeginInteract() {
   if (CanInteract()) {
     interacting_ = true;
@@ -144,6 +163,19 @@ bool NpcObject::IsAnimationFinished() const {
 
 void NpcObject::Update(float deltaTime) {
   Actor::Update(deltaTime);
+  SyncInteractionHighlight();
+}
+
+void NpcObject::EnsureInteractionHighlight() {
+  if (interactionHighlight_) {
+    return;
+  }
+
+  interactionHighlight_ = MakePtr<InteractionHighlightSprite>();
+  interactionHighlight_->SetZOrder(-1);
+  interactionHighlight_->SetPosition(0.0f, 0.0f);
+  interactionHighlight_->SetVisible(false);
+  AddChild(interactionHighlight_);
 }
 
 void NpcObject::EnsureNameLabel() {
@@ -206,6 +238,38 @@ void NpcObject::RefreshNameLabel() {
   }
 }
 
+void NpcObject::SyncInteractionHighlight() {
+  if (!interactionHighlight_) {
+    return;
+  }
+
+  if (!interactionHighlighted_ || !animation_ ||
+      !animation_->EnsureCompositeTextureReady() ||
+      !animation_->HasCompositeTexture()) {
+    interactionHighlight_->SetVisible(false);
+    return;
+  }
+
+  uint64 compositeVersion = animation_->GetCompositeVersion();
+  if (syncedHighlightCompositeVersion_ != compositeVersion) {
+    Ptr<Texture> compositeTexture = animation_->GetCompositeTexture();
+    Vec2 compositeSize = animation_->GetCompositeTextureSize();
+    if (!compositeTexture || compositeSize.x <= 0.0f || compositeSize.y <= 0.0f) {
+      interactionHighlight_->SetVisible(false);
+      return;
+    }
+
+    interactionHighlight_->SetTexture(compositeTexture);
+    interactionHighlight_->SetSize(compositeSize);
+    interactionHighlight_->SetGroundAnchorInTexture(
+        animation_->GetCompositeGroundAnchorInTexture());
+    interactionHighlight_->SetPosition(0.0f, 0.0f);
+    syncedHighlightCompositeVersion_ = compositeVersion;
+  }
+
+  interactionHighlight_->SetVisible(true);
+}
+
 void NpcObject::SyncActorPositionFromWorld() {
   SetPosition(worldPosition_.ToScreenPosition());
   SetZOrder(worldPosition_.y);