feat(chat): 채팅 모듈 하드코딩 문구를 I18n 키로 통일한다

SodaLive/Sources/Chat/Talk/Room/Settings/ChatBgSelectionView.swift

@@ -26,7 +26,7 @@ struct ChatBgSelectionView: View {
     var body: some View {
         BaseView(isLoading: $viewModel.isLoading) {
             VStack(spacing: 0) {
-                DetailNavigationBar(title: String(localized: "배경 이미지 선택")) {
+                DetailNavigationBar(title: I18n.Chat.Room.backgroundSelectionTitle) {
                     isShowing = false
                 }
                 // 갤러리 그리드
@@ -79,7 +79,7 @@ struct ChatBgSelectionView: View {
                 }
                 
                 if selectedBgImageId == item.id {
-                    Text("현재 배경")
+                    Text(I18n.Chat.Room.currentBackground)
                         .appFont(size: 12, weight: .regular)
                         .foregroundColor(.white)
                         .padding(.horizontal, 6)