Plan Module / Package Structure

Background: Native [platform] app, [SwiftUI / Compose], architecture is
[your choice]. Right now everything is in one target/module and it's
getting unwieldy. Features: [list].

Use case: Help me split the app into modules/packages so builds stay
fast, features stay isolated, and code can be reused.

Implementation details:
- iOS: think in Swift Package Manager local packages / framework targets
- Android: think in Gradle modules
- Decide between layer-based modules (UI/domain/data) vs feature-based
  modules (per feature) vs a hybrid—recommend one for my app
- Identify a shared "core"/"common" module and what belongs in it
- Avoid circular dependencies

Layer & dependencies: Show the module dependency graph and confirm it's
acyclic.

Deliverable: A proposed module list with each module's purpose, the
dependency graph (text), the tradeoffs of the chosen structure, and a
safe step-by-step order to extract modules from the current monolith.