refactor(data): replace schema classes with readonly models

src/stores/private-room/private-room-state.ts

@@ -1,5 +1,5 @@
-import type { PrivateAlbum } from "@/data/schemas/private-room";
 import { DEFAULT_CHARACTER_ID } from "@/data/constants/character";
+import type { PrivateAlbum } from "@/data/schemas/private-room";
 
 export interface PrivateRoomUnlockPaywallRequest {
   albumId: string;
@@ -11,7 +11,7 @@ export interface PrivateRoomUnlockPaywallRequest {
 
 export interface PrivateRoomState {
   characterId: string;
-  items: PrivateAlbum[];
+  items: readonly PrivateAlbum[];
   creditBalance: number;
   errorMessage: string | null;
   unlockingAlbumId: string | null;