feat(chat): 채팅 탭 추가 및 캐릭터/톡 내부 탭 구현

- ChatTabView 신설: 앱 바 + 내부 탭(캐릭터/톡) 전환 구성
- 커스텀 탭 적용
  - indicatorHeight: 4, indicatorColor: #3bb9f1
  - tabText color: #b0bec5
  - 폰트: 선택 전 Pretendard-Regular, 선택 후 Pretendard-Bold
- HomeView/BottomTabView에 ChatTabView 연동
- CharacterView/TalkView 플레이스홀더 추가

SodaLive/Sources/Main/Home/HomeView.swift

@@ -19,6 +19,7 @@ struct HomeView: View {
     
     private let liveView = LiveView()
     private let homeTabView = HomeTabView()
+    private let chatTabView = ChatTabView()
     
     @State private var isShowPlayer = false
     @AppStorage("token") private var token: String = UserDefaults.string(forKey: UserDefaultsKey.token)
@@ -32,6 +33,10 @@ struct HomeView: View {
                             .frame(width: viewModel.currentTab == .home ? proxy.size.width : 0)
                             .opacity(viewModel.currentTab == .home ? 1.0 : 0.01)
                         
+                        chatTabView
+                            .frame(width: viewModel.currentTab == .chat ? proxy.size.width : 0)
+                            .opacity(viewModel.currentTab == .chat ? 1.0 : 0.01)
+                        
                         liveView
                             .frame(width: viewModel.currentTab == .live ? proxy.size.width : 0)
                             .opacity(viewModel.currentTab == .live ? 1.0 : 0.01)