Rebuild in-app navigation on iOS and Android

Not ready — and that is the point

This is tagged Needs Refinement on purpose, as a worked example of what an unready item looks like.

Why it fails the Definition of Ready (section 5 of How to use this Agile template):

• No acceptance criteria — "rebuild navigation" could mean a week or a quarter
• Blocked by a spec and a prototype that are both unfinished
• Almost certainly larger than 8 points, so it must be split before it can enter a sprint
• No decision yet on whether existing deep links keep working

How it should be split, once the spike reports back:

1. Navigation shell and routing on iOS
2. Navigation shell and routing on Android
3. Deep link compatibility layer
4. Migrate existing screens into the new shell

Depends on

• Write the mobile navigation spec
• Build the mobile navigation prototype

Do not pull this into a sprint to fill space. The guide explains why that habit costs more than an under-filled sprint.