Product icons are missing from the Xcode project

The `ProductIcons` folder exists in the repository and contains the Icon Composer assets, but the folder is not included in the Xcode project.

The app icon configuration names also still reference the previous asset catalogue icon names, causing builds to use a placeholder icon instead of the corresponding Icon Composer asset.

## Expected behaviour

The `ProductIcons` folder should be included in the Xcode project and each build configuration should reference its corresponding Icon Composer asset.

Start by opening the Xcode project and inspecting how the ProductIcons folder and Icon Composer assets are represented. Compare the app icon configuration names across build configurations with the assets in ProductIcons, then build the app and verify each configuration uses its corresponding icon rather than a placeholder.

索引モデルが issue の本文から書いたものです。