test(api): add channel monitor fields to admin settings contract test

backend/internal/server/api_contract_test.go

@@ -768,6 +768,9 @@ func TestAPIContracts(t *testing.T) {
 					"balance_low_notify_threshold": 0,
 					"balance_low_notify_recharge_url": "",
 					"account_quota_notify_emails": [],
+					"channel_monitor_enabled": true,
+					"channel_monitor_default_interval_seconds": 60,
+					"available_channels_enabled": false,
 					"wechat_connect_enabled": false,
 					"wechat_connect_app_id": "",
 					"wechat_connect_app_secret_configured": false,
@@ -939,6 +942,9 @@ func TestAPIContracts(t *testing.T) {
 					"balance_low_notify_threshold": 0,
 					"balance_low_notify_recharge_url": "",
 					"account_quota_notify_emails": [],
+					"channel_monitor_enabled": true,
+					"channel_monitor_default_interval_seconds": 60,
+					"available_channels_enabled": false,
 					"wechat_connect_enabled": true,
 					"wechat_connect_app_id": "wx-open-config",
 					"wechat_connect_app_secret_configured": true,