fix(openai): 修复 Groq 服务层级类型不匹配问题

将 service_tier 强制转换为 OpenAIServiceTier 类型，因为 Groq 的服务层级配置与 OpenAI 接口类型不兼容

src/renderer/src/aiCore/clients/openai/OpenAIApiClient.ts

@@ -39,6 +39,7 @@ import {
   MCPTool,
   MCPToolResponse,
   Model,
+  OpenAIServiceTier,
   Provider,
   ToolCallResponse,
   TranslateAssistant,
@@ -560,7 +561,8 @@ export class OpenAIAPIClient extends OpenAIBaseClient<
           top_p: this.getTopP(assistant, model),
           max_tokens: maxTokens,
           tools: tools.length > 0 ? tools : undefined,
-          service_tier: this.getServiceTier(model),
+          // groq 有不同的 service tier 配置，不符合 openai 接口类型
+          service_tier: this.getServiceTier(model) as OpenAIServiceTier,
           ...this.getProviderSpecificParameters(assistant, model),
           ...this.getReasoningEffort(assistant, model),
           ...getOpenAIWebSearchParams(model, enableWebSearch),