fix(settings): wait for complete Jimeng login challenge

Do not return a device login challenge until both the URI and user code arrive.

Force split CLI output in the regression test to cover Linux pipe timing.

Author: y2hlbg

services/server/internal/service/settings/store.go

@@ -335,7 +335,7 @@ func (service *Settings) startJimengLogin(ctx context.Context) (ProviderLoginCha
 		select {
 		case text := <-output.updates:
 			login := parseJimengLoginChallenge([]byte(text))
-			if login.Status == "pending" && login.VerificationURI != "" {
+			if login.Status == "pending" && login.VerificationURI != "" && login.UserCode != "" {
 				login.DeviceCode = ""
 				if login.Message == "" {
 					login.Message = "即梦登录链接已生成，请在浏览器中完成登录。"

services/server/internal/service/settings/store_test.go

@@ -333,6 +333,7 @@ func TestSettingsJimengBrowserLoginReturnsChallengeAndPersistsAfterCLICompletes(
 	script := `#!/bin/sh
 if [ "$1" = "login" ] && [ "$#" -eq 1 ]; then
   echo "verification_uri: https://example.test/device"
+  sleep 0.05
   echo "user_code: ABCD-EFGH"
   echo "device_code: device-123"
   sleep 0.2