fix(universal): 映射脚本上游模型名

让 server-main 参数预处理兼容上下文使用平台绑定的真实模型名，避免把用户侧别名提交给上游。

apps/api/internal/clients/universal_test.go

@@ -102,7 +102,7 @@ func TestUniversalClientSupportsServerMainScriptContextAndNestedResult(t *testin
 			"customGetParamsScript": map[string]any{
 				"image_generate": `async function getParams(params, context) {
 					const processed = await context.preProcessParams(params, context.type);
-					return { prompt: processed.prompt + "-" + context.processedParams.prompt };
+					return { prompt: processed.prompt + "-" + processed.model + "-" + context.processedParams.model };
 				}`,
 			},
 			"customSubmitScript": map[string]any{
@@ -128,7 +128,7 @@ func TestUniversalClientSupportsServerMainScriptContextAndNestedResult(t *testin
 		t.Fatalf("unexpected nested result: %#v", response.Result)
 	}
 	image, ok := data[0].(map[string]any)
-	if !ok || image["url"] != "https://cdn.example/hello-hello.png" {
+	if !ok || image["url"] != "https://cdn.example/hello-provider-model-provider-model.png" {
 		t.Fatalf("unexpected image result: %#v", response.Result)
 	}
 }