fix: Dispatchers.Default pour la compat native iOS (IO internal en K/N)

sharedUI/src/commonMain/kotlin/com/livrets/data/HistoryRepository.kt

@@ -14,7 +14,7 @@ class HistoryRepository(
 ) {
     private val json = Json { ignoreUnknownKeys = true }
 
-    suspend fun load(): List<GameResult> = withContext(Dispatchers.IO) {
+    suspend fun load(): List<GameResult> = withContext(Dispatchers.Default) {
         if (!fileSystem.exists(filePath)) return@withContext emptyList()
         fileSystem.read(filePath) { readUtf8() }
             .let { json.decodeFromString(ListSerializer(GameResult.serializer()), it) }
@@ -22,7 +22,7 @@ class HistoryRepository(
 
     suspend fun save(result: GameResult) {
         val all = load() + result
-        withContext(Dispatchers.IO) {
+        withContext(Dispatchers.Default) {
             filePath.parent?.let { fileSystem.createDirectories(it) }
             fileSystem.write(filePath) {
                 writeUtf8(json.encodeToString(ListSerializer(GameResult.serializer()), all))