Write the mobile navigation spec

Goal

One navigation model that works on both iOS and Android, written down before anyone builds it.

Deliverable

A written spec, not code. It is Done when another engineer could build from it without asking questions.

Acceptance criteria

• Every screen and the routes between them mapped
• Back-stack behavior defined for both platforms, including the Android hardware back button
• Deep link handling specified
• Empty, loading, and error states covered for each screen
• Platform conventions respected — tab bar on iOS, navigation drawer or bottom bar on Android. Do not ship one platform's pattern on the other
• Reviewed by both platform leads

Blocks

• Build the mobile navigation prototype
• Rebuild in-app navigation on iOS and Android