perf: 优化工作流的节点UI和交互

easyflow-ui-admin/packages/tinyflow-ui/src/components/nodes/LLMNode.svelte

@@ -29,7 +29,53 @@
     let llmArray = $state<SelectItem[]>([]);
     onMount(async () => {
         const newLLMs = await options.provider?.llm?.();
-        llmArray.push(...(newLLMs || []));
+        
+        const isFlat = newLLMs?.every(item => !item.children);
+        
+        if (isFlat && newLLMs && newLLMs.length > 0) {
+            const grouped = new Map<string, SelectItem[]>();
+            for (const llm of newLLMs) {
+                // If it still has a slash, parse it; otherwise, check if there's a custom logic we can infer brand.
+                // In WorkflowDesign we pass `item.modelProvider?.providerName` via some other way, but here it's flat.
+                // Actually, the label is just the title now (e.g. 'deepseek-chat').
+                // Wait, LLMNode doesn't know the brand unless it's in the string or we modify WorkflowDesign to pass `brand`.
+                // Let's modify WorkflowDesign to pass `brand` instead.
+                let brand = (llm as any).brand || '其他';
+                let modelName = llm.label;
+                
+                if (!grouped.has(brand)) {
+                    grouped.set(brand, []);
+                }
+                grouped.get(brand)!.push({
+                    ...llm,
+                    label: modelName,
+                    displayLabel: modelName // 外部选中时也只显示模型名称
+                });
+            }
+
+            const treeArray: SelectItem[] = [];
+            for (const [brand, models] of grouped) {
+                // Try to get a representative icon for the brand from its children
+                let groupIcon = undefined;
+                if (models.length > 0) {
+                    const modelWithIcon = models.find(m => m.icon);
+                    if (modelWithIcon) {
+                        groupIcon = modelWithIcon.icon;
+                    }
+                }
+                
+                treeArray.push({
+                    label: brand,
+                    value: 'group_' + brand,
+                    selectable: false,
+                    icon: groupIcon,
+                    children: models
+                });
+            }
+            llmArray.push(...treeArray);
+        } else {
+            llmArray.push(...(newLLMs || []));
+        }
     });
 
     const { updateNodeData } = useSvelteFlow();
@@ -116,7 +162,7 @@
     <Heading level={3} mt="10px">模型设置</Heading>
     <div class="setting-title">模型</div>
     <div class="setting-item">
-        <Select items={llmArray} style="width: 100%" placeholder="请选择模型" onSelect={(item)=>{
+        <Select items={llmArray} variant="model" style="width: 100%" placeholder="请选择模型" onSelect={(item)=>{
               const newValue = item.value;
               updateNodeData(currentNodeId, ()=>{
                   return {