refactor: remove close button and AI button from NodeEditor header

editor/components/NodeEditor.vue

@@ -10,7 +10,6 @@ const props = defineProps<{
 
 const emit = defineEmits<{
   deleteScene: [id: string]
-  close: []
 }>()
 
 const store = useEditorStore()
@@ -62,10 +61,8 @@ function onBlur() {
           <div class="header-actions">
             <span v-if="saved" class="saved-hint">已保存</span>
             <span v-if="errorMsg" class="error-hint">JSON 错误: {{ errorMsg }}</span>
-            <button class="icon-btn" @click="store.showAIPanel = true" title="AI 助手">🤖</button>
             <button class="icon-btn" @click="store.nodeEditorCollapsed = true" title="折叠">▶</button>
             <button v-if="scene" class="icon-btn danger" @click="emit('deleteScene', scene.id)" title="删除场景">🗑</button>
-            <button v-if="scene" class="icon-btn" @click="emit('close')" title="关闭">✕</button>
           </div>
         </div>