lock gigachat api

feature/chat/chat-backend/src/main/kotlin/ru/shadowsparky/chat/backend/data/GigaChatService.kt

@@ -8,6 +8,8 @@ import io.ktor.client.request.post
 import io.ktor.client.request.setBody
 import io.ktor.http.ContentType
 import io.ktor.http.contentType
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import org.koin.core.annotation.Single
@@ -21,6 +23,7 @@ class GigaChatService(
     private val tokenManager: GigaChatTokenManager,
     private val httpClientFactory: HttpClientFactory
 ) : ChatService {
+    private val mutex = Mutex()
     private val httpClient by lazy {
         httpClientFactory.create(
             BearerAuthProvider(
@@ -36,7 +39,7 @@ class GigaChatService(
         )
     }
 
-    override suspend fun getCompletion(userId: Long, messages: List<Message>): String {
+    override suspend fun getCompletion(userId: Long, messages: List<Message>): String = mutex.withLock {
         val clientId = "vbox-$userId"
         val staticSessionId = UUID.nameUUIDFromBytes(clientId.toByteArray()).toString()
         val requestBody = GigaChatRequest(