Update mobile dependencies to Expo SDK 54 (#203)

Upgrades the Expo SDK to version 54 and aligns core dependencies:
- Upgrades `expo` to `^54.0.25`.
- Upgrades `react-native` to `0.81.5`.
- Upgrades `react` and `react-dom` to `19.1.0`.
- Updates `expo-image-picker`, `expo-status-bar`, and `@expo/metro-runtime` to compatible versions.
- Regenerates `package-lock.json`.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: google-labs-jules[bot]