style: satisfy Sonnet 5.5 lint checks

backend/internal/service/gateway_anthropic_apikey_passthrough_test.go

@@ -1830,10 +1830,11 @@ func TestSonnet55RejectsUnsupportedParametersBeforeMimicry(t *testing.T) {
 			for _, count := range []bool{false, true} {
 				model := "claude-sonnet-5-5"
 				account := &Account{ID: 1, Platform: PlatformAnthropic, Type: typ}
-				if typ == AccountTypeAPIKey {
+				switch typ {
+				case AccountTypeAPIKey:
 					model = "public-sonnet"
 					account.Credentials = map[string]any{"model_mapping": map[string]any{model: "claude-sonnet-5-5"}}
-				} else if typ == AccountTypeBedrock {
+				case AccountTypeBedrock:
 					account.Credentials = map[string]any{"aws_region": "eu-west-1"}
 				}
 				body := []byte(`{"model":"` + model + `","messages":[{"role":"user","content":"hello"}],` + field + `}`)

backend/internal/service/gateway_request.go

@@ -736,7 +736,7 @@ func FilterThinkingBlocksForRetry(body []byte, mappedModel string) []byte {
 	// Disable top-level thinking mode for retry to avoid structural/signature constraints upstream.
 	thinkingMode := gjson.Get(jsonStr, "thinking.type").String()
 	deleteTopLevelThinking := gjson.Get(jsonStr, "thinking").Exists() &&
-		!(claude.IsSonnet55(mappedModel) && thinkingMode == "between_tools")
+		(!claude.IsSonnet55(mappedModel) || thinkingMode != "between_tools")
 
 	for i := 0; i < len(messages); i++ {
 		msgMap, ok := messages[i].(map[string]any)