feat: 优化阿里生图模型错误提示，使用后台配置的模型名称

- 错误提示中显示后台配置的模型显示名称
- 添加 modelDisplayName 参数到 doGenerate 接口
- 当用户只发文字时，提示需要上传图片

app/(chat)/api/chat/route.ts

@@ -897,6 +897,10 @@ export async function POST(request: Request) {
       console.log("[Chat API] Using Alibaba Image generation");
       console.log("[Chat API] Image params:", requestBody.imageParams);
       
+      // 🆕 获取模型显示名称，用于错误提示
+      const alibabaModelConfig = await getAiModelById({ id: finalModelId });
+      const modelDisplayName = alibabaModelConfig?.displayName || actualModelId;
+      
       const alibabaStream = createUIMessageStream({
         execute: async ({ writer }) => {
           try {
@@ -908,10 +912,11 @@ export async function POST(request: Request) {
             // 转换消息（阿里生图支持 URL，会自动上传 base64）
             const modelMessages = await convertMessagesWithImages(messagesForAlibaba, "alibaba-image");
             
-            // 调用 doGenerate 获取图片
+            // 调用 doGenerate 获取图片，传递模型显示名称
             const result = await (languageModel as any).doGenerate({
               messages: modelMessages,
               imageParams: requestBody.imageParams || { aspectRatio: "auto", imageSize: "2K", imageCount: 1 },
+              modelDisplayName, // 🆕 传递模型显示名称
             });
             
             const imageMarkdown = result.text || "图片生成失败";

lib/ai/providers/alibaba-image.ts

@@ -286,6 +286,7 @@ export function createAlibabaImage({ apiKey, baseURL }: AlibabaImageConfig) {
       doGenerate: async (options: {
         messages: Array<{ role: string; content: string | Array<{ type: string; text?: string; image?: string }> }>;
         imageParams?: AlibabaImageParams & { aspectRatio?: string; imageSize?: string; imageCount?: number };
+        modelDisplayName?: string; // 🆕 模型显示名称，用于错误提示
       }) => {
         console.log("[Alibaba Image] doGenerate called");
         console.log("[Alibaba Image] Model:", modelId);
@@ -344,6 +345,12 @@ export function createAlibabaImage({ apiKey, baseURL }: AlibabaImageConfig) {
             throw new Error("No prompt found in message");
           }
           
+          // 验证：qwen-image-edit 系列模型必须有输入图片
+          if (imageUrls.length === 0) {
+            const modelName = options.modelDisplayName || modelId;
+            throw new Error(`「${modelName}」是图片编辑模型，需要至少上传一张图片才能进行编辑。如需纯文生图，请使用其他生图模型。`);
+          }
+          
           // 构建参数
           const params: AlibabaImageParams = {
             n: options.imageParams?.imageCount || options.imageParams?.n || 1,
@@ -366,7 +373,10 @@ export function createAlibabaImage({ apiKey, baseURL }: AlibabaImageConfig) {
             params.size = sizeMap[options.imageParams.imageSize] || "1024*1024";
           }
           
-          console.log("[Alibaba Image] Prompt:", prompt.substring(0, 100) + "...");
+          // 根据图片数量确定编辑模式
+          const editMode = imageUrls.length === 1 ? "单图编辑" : `多图融合 (${imageUrls.length}张)`;
+          console.log("[Alibaba Image] 编辑模式:", editMode);
+          console.log("[Alibaba Image] Prompt:", prompt.substring(0, 100) + (prompt.length > 100 ? "..." : ""));
           console.log("[Alibaba Image] Input images:", imageUrls.length);
           console.log("[Alibaba Image] Final params:", params);
           
@@ -403,6 +413,7 @@ export function createAlibabaImage({ apiKey, baseURL }: AlibabaImageConfig) {
       doStream: async function* (options: {
         messages: Array<{ role: string; content: string | Array<{ type: string; text?: string; image?: string }> }>;
         imageParams?: AlibabaImageParams & { aspectRatio?: string; imageSize?: string; imageCount?: number };
+        modelDisplayName?: string;
       }) {
         console.log("[Alibaba Image] doStream called (using doGenerate internally)");