refactor(preferences): DataStore 설정 저장 안정성을 높인다

app/src/main/java/kr/co/vividnext/sodalive/settings/language/LanguageManager.kt

@@ -1,21 +1,14 @@
 package kr.co.vividnext.sodalive.settings.language
 
 import android.content.Context
-import android.content.SharedPreferences
 import android.os.Build
-import androidx.core.content.edit
-import androidx.preference.PreferenceManager
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
 
 object LanguageManager {
     const val LANG_KO = "ko"
     const val LANG_EN = "en"
     const val LANG_JA = "ja"
 
-    private const val PREF_KEY_APP_LANGUAGE = "pref_app_language_code"
-
-    private fun prefs(context: Context): SharedPreferences =
-        PreferenceManager.getDefaultSharedPreferences(context.applicationContext)
-
     fun isSupported(code: String): Boolean = when (code) {
         LANG_KO, LANG_EN, LANG_JA -> true
         else -> false
@@ -25,8 +18,9 @@ object LanguageManager {
      * 사용자가 앱 내에서 명시적으로 선택한 언어 코드를 반환한다. 없으면 null.
      */
     fun getUserSelectedLanguageOrNull(context: Context): String? {
-        val code = prefs(context).getString(PREF_KEY_APP_LANGUAGE, null)
-        return code?.takeIf { it.isNotBlank() }
+        SharedPreferenceManager.init(context.applicationContext)
+        val code = SharedPreferenceManager.appLanguageCode
+        return code.takeIf { it.isNotBlank() }
     }
 
     /**
@@ -64,6 +58,7 @@ object LanguageManager {
 
     fun setSelectedLanguage(context: Context, code: String) {
         val normalized = if (isSupported(code)) code else LANG_KO
-        prefs(context).edit { putString(PREF_KEY_APP_LANGUAGE, normalized) }
+        SharedPreferenceManager.init(context.applicationContext)
+        SharedPreferenceManager.appLanguageCode = normalized
     }
 }