You're developing a Python program for "Paws and Claws Pet Emporium," an online pet supply store. The store offers three flagship products: Premium Dog Food, Deluxe Cat Litter, and Interactive Pet Toys. Could you outline the logic and structure of a program that provides information about these products, including features, prices, and specifications? Requirements: Display details for each product, such as ingredients (for food), material (for litter), and features (for toys). Implement a shopping cart functionality that allows users to add products, specify quantities, and calculate the total cost. Incorporate a discount system where users get a 5% discount on the total cost if they purchase all three flagship products together. Include an optional section for users to select pet size-specific options or leave special instructions related to their pets. Output a summary of the user's selected products, quantities, total cost, selected pet size options, and any additional instructions after they interact with the shopping cart.