fix: 修复 huanke-gemini 占位图不显示问题

- 在 messages.tsx 中将 huanke-gemini 和 gemini-image 纳入 isGeminiModel 判断
- 在 chat.tsx 中将 huanke-gemini 和 gemini-image 记录为 gemini 类型的生成任务
- 确保使用 huanke-gemini 时显示 Gemini 图片生成占位图

components/chat.tsx

@@ -425,7 +425,8 @@ export function Chat({
       const model = models?.find((m: any) => m.id === currentModelId);
       
       let modelType: PendingGeneration["modelType"] = "other";
-      if (model?.providerType === "gemini") modelType = "gemini";
+      // 🆕 gemini-image 和 huanke-gemini 都视为 gemini 类型
+      if (model?.providerType === "gemini" || model?.providerType === "gemini-image" || model?.providerType === "huanke-gemini") modelType = "gemini";
       else if (model?.providerType === "volcano-vision") modelType = "volcano-vision";
       else if (model?.providerType === "volcano-video") modelType = "volcano-video";
       else if (model?.providerType === "qianwen-video") modelType = "qianwen-video";

components/messages.tsx

@@ -94,8 +94,9 @@ function PureMessages({
   );
 
   // 判断当前选中的模型类型
+  // 🆕 包含 gemini 和 huanke-gemini 两种 Gemini 图片生成 provider
   const isGeminiModel = modelsData?.models?.some(
-    (m: DynamicModel) => m.id === selectedModelId && m.providerType === "gemini"
+    (m: DynamicModel) => m.id === selectedModelId && (m.providerType === "gemini" || m.providerType === "gemini-image" || m.providerType === "huanke-gemini")
   ) ?? false;
   
   const isQianwenVideoModel = modelsData?.models?.some(