Feat(shop): Add new feature like notes skin

[narainkarthikv]

• [ ] Design and implement a feature to allow users to change note skins (themes or styles).
• [ ] Create multiple skin options for notes (e.g., different colors, textures, or layouts).
• [ ] Add a UI element in the shop to let users select and purchase note skins.
• [ ] Ensure note skins are applied consistently across all user devices.
• [ ] Store selected note skins in user settings for persistence.
• [ ] Test compatibility of skins with other features like drag-and-drop and sorting.
• [ ] Update documentation to explain how the note skin feature works.