fix: 让消息 cache_control 改写默认关闭

backend/internal/server/api_contract_test.go

@@ -773,6 +773,7 @@ func TestAPIContracts(t *testing.T) {
 					"backend_mode_enabled": false,
 					"enable_cch_signing": false,
 					"enable_anthropic_cache_ttl_1h_injection": false,
+					"rewrite_message_cache_control": false,
 					"enable_fingerprint_unification": true,
 					"enable_metadata_passthrough": false,
 					"web_search_emulation_enabled": false,
@@ -988,6 +989,7 @@ func TestAPIContracts(t *testing.T) {
 					"enable_metadata_passthrough": false,
 					"enable_cch_signing": false,
 					"enable_anthropic_cache_ttl_1h_injection": false,
+					"rewrite_message_cache_control": false,
 					"web_search_emulation_enabled": false,
 					"payment_visible_method_alipay_source": "",
 					"payment_visible_method_wxpay_source": "",