/rn-screen: add a mobile screen/feature

Follow mobile/CLAUDE.md.

1. Data: which endpoints? Make sure src/api/schema.d.ts is current (npm run gen:api). Add query keys and a hook in src/features/<feature>/ (useQuery / useInfiniteQuery / useMutation with cache invalidation).
2. Route: add a thin file under app/ that composes feature components. Choose the presentation (tab, stack push, or modal).
3. States: design loading (skeleton), empty (especially a new user with no runs), error (retry), and success.
4. UI: use components/ui primitives and theme tokens only. Dark-first. Use the Wrapped token set only inside the Wrapped experience.
5. Formatting: distances, paces, and durations go through src/lib/format.ts in the user's preferred units.
6. Motion: Reanimated on the UI thread. Respect useReducedMotion.
7. Accessibility: labels on icon buttons, a text summary for charts, and tap targets of at least 44pt.
8. Tests: unit tests for any new util. Use RNTL for state rendering, mocking at the fetch layer.
9. Run npm run typecheck && npm run lint && npm test, then tell the user exactly what to check in the simulator.