SwiftPM Modularization

When to invoke

• Starting a new Swift App project and deciding how to split modules.
• Writing the first version of Package.swift.
• Wanting to reserve the option of shipping core logic to Android / cross-platform later.
• Introducing CloudKit / GameKit / StoreKit and deciding the import scope.
• User asks "single Package or multiple", "should the App target be thin", "how do I wire DI".

Default decisions

Single Package + multiple targets

• Put all modules in one Swift Package, splitting by target (named e.g. <Project>Kit).
• Don't start with multiple Packages — they only add Package.swift maintenance cost and CI resolution time.

Very thin App target