feat(i18n): 번역 작업 큐와 언어 감지 캐시를 도입한다

조회 중 외부 번역 호출을 줄이고 누락 번역을 비동기 job으로 처리한다.

src/test/kotlin/kr/co/vividnext/sodalive/content/AudioContentServiceTest.kt

@@ -18,7 +18,7 @@ import kr.co.vividnext.sodalive.content.translation.ContentTranslationRepository
 import kr.co.vividnext.sodalive.explorer.ExplorerQueryRepository
 import kr.co.vividnext.sodalive.i18n.LangContext
 import kr.co.vividnext.sodalive.i18n.SodaMessageSource
-import kr.co.vividnext.sodalive.i18n.translation.PapagoTranslationService
+import kr.co.vividnext.sodalive.i18n.translation.ResourceTranslationJobScheduler
 import kr.co.vividnext.sodalive.member.Member
 import kr.co.vividnext.sodalive.member.block.BlockMemberRepository
 import org.junit.jupiter.api.Assertions.assertEquals
@@ -44,7 +44,7 @@ class AudioContentServiceTest {
     private lateinit var commentRepository: AudioContentCommentRepository
     private lateinit var audioContentLikeRepository: AudioContentLikeRepository
     private lateinit var pinContentRepository: PinContentRepository
-    private lateinit var translationService: PapagoTranslationService
+    private lateinit var resourceTranslationJobScheduler: ResourceTranslationJobScheduler
     private lateinit var contentTranslationRepository: ContentTranslationRepository
     private lateinit var s3Uploader: S3Uploader
     private lateinit var audioContentCloudFront: AudioContentCloudFront
@@ -66,7 +66,7 @@ class AudioContentServiceTest {
         commentRepository = Mockito.mock(AudioContentCommentRepository::class.java)
         audioContentLikeRepository = Mockito.mock(AudioContentLikeRepository::class.java)
         pinContentRepository = Mockito.mock(PinContentRepository::class.java)
-        translationService = Mockito.mock(PapagoTranslationService::class.java)
+        resourceTranslationJobScheduler = Mockito.mock(ResourceTranslationJobScheduler::class.java)
         contentTranslationRepository = Mockito.mock(ContentTranslationRepository::class.java)
         s3Uploader = Mockito.mock(S3Uploader::class.java)
         audioContentCloudFront = Mockito.mock(AudioContentCloudFront::class.java)
@@ -85,7 +85,7 @@ class AudioContentServiceTest {
             commentRepository = commentRepository,
             audioContentLikeRepository = audioContentLikeRepository,
             pinContentRepository = pinContentRepository,
-            translationService = translationService,
+            resourceTranslationJobScheduler = resourceTranslationJobScheduler,
             contentTranslationRepository = contentTranslationRepository,
             s3Uploader = s3Uploader,
             objectMapper = ObjectMapper(),

src/test/kotlin/kr/co/vividnext/sodalive/content/LanguageDetectionCacheServiceTest.kt

@@ -0,0 +1,42 @@
+package kr.co.vividnext.sodalive.content
+
+import kr.co.vividnext.sodalive.i18n.translation.SourceTextNormalizer
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.mockito.Mockito
+
+class LanguageDetectionCacheServiceTest {
+    @Test
+    fun shouldReuseCachedLanguageDetectionForSameNormalizedText() {
+        val repository = Mockito.mock(LanguageDetectionResultRepository::class.java)
+        val service = LanguageDetectionCacheService(repository)
+        val sourceHash = SourceTextNormalizer.hash("Hello world")
+
+        Mockito.`when`(
+            repository.findBySourceHashAndProviderAndNormalizationVersion(
+                sourceHash = sourceHash,
+                provider = "papago",
+                normalizationVersion = SourceTextNormalizer.NORMALIZATION_VERSION
+            )
+        ).thenReturn(
+            LanguageDetectionResult(
+                sourceHash = sourceHash,
+                sourceTextSample = "Hello world",
+                detectedLanguage = "en",
+                provider = "papago",
+                confidence = null,
+                normalizationVersion = SourceTextNormalizer.NORMALIZATION_VERSION
+            )
+        )
+
+        var providerCalls = 0
+        val detected = service.detectWithCache("Hello   world") {
+            providerCalls++
+            "ko"
+        }
+
+        assertEquals("en", detected)
+        assertEquals(0, providerCalls)
+        Mockito.verify(repository, Mockito.never()).save(Mockito.any(LanguageDetectionResult::class.java))
+    }
+}