fix(model): 支持不设置推理强度

internal/client/model_adapter_benchmark.go

@@ -950,6 +950,8 @@ func normalizeModelAdapterTestType(value string) string {
 
 func normalizeModelAdapterTestReasoning(value string) string {
 	switch strings.ToLower(strings.TrimSpace(value)) {
+	case "":
+		return ""
 	case "low", "medium", "high", "xhigh", "max":
 		return strings.ToLower(strings.TrimSpace(value))
 	default:

internal/client/model_adapter_benchmark_test.go

@@ -0,0 +1,15 @@
+package client
+
+import (
+	"testing"
+
+	serverconfig "cursor/internal/backend/server/config"
+)
+
+func TestNormalizeModelAdapterTestProviderReasoningPreservesBlank(t *testing.T) {
+	adapter := serverconfig.ModelAdapterConfig{Type: "openai", ReasoningEffort: ""}
+
+	if got := normalizeModelAdapterTestProviderReasoning(adapter); got != "" {
+		t.Fatalf("reasoning effort = %q, want blank", got)
+	}
+}