feat(character): 캐릭터 메인 화면 구현 및 Combine 기반 리팩터링

- 배너/최근/신규/큐레이션 섹션 UI 구성 및 데이터 바인딩
- 네트워크 이미지 로더를 Kingfisher(KFImage)로 교체하여 캐싱/재시도 지원
- CharacterApi에 토큰 헤더 포함, GET /api/chat/character/main 연동

SodaLive/Sources/Chat/Character/CharacterItemView.swift

@@ -0,0 +1,50 @@
+//
+//  CharacterItemView.swift
+//  SodaLive
+//
+//  Created by klaus on 8/29/25.
+//
+
+import SwiftUI
+import Kingfisher
+
+struct CharacterItemView: View {
+    
+    let character: Character
+    let size: CGFloat
+    
+    var body: some View {
+        VStack(alignment: .leading, spacing: 4) {
+            KFImage(URL(string: character.imageUrl))
+                .placeholder { Color.gray.opacity(0.2) }
+                .retry(maxCount: 2, interval: .seconds(1))
+                .cancelOnDisappear(true)
+                .resizable()
+                .scaledToFill()
+                .frame(width: size, height: size)
+                .clipped()
+                .cornerRadius(12)
+            
+            Text(character.name)
+                .font(.custom(Font.preRegular.rawValue, size: 18))
+                .foregroundColor(.white)
+                .lineLimit(1)
+                .truncationMode(.tail)
+            
+            if let desc = character.description, !desc.isEmpty {
+                Text(desc)
+                    .font(.custom(Font.preRegular.rawValue, size: 14))
+                    .foregroundColor(Color(hex: "78909C"))
+                    .lineLimit(1)
+            }
+        }
+        .frame(width: size, alignment: .leading)
+    }
+}
+
+#Preview {
+    CharacterItemView(
+        character: Character(characterId: 1, name: "찰리", description: "새로운 친구", imageUrl: "https://picsum.photos/300"),
+        size: 168
+    )
+}