Build mobile rewards wallet screen with claim and history UX

[S-Mubarak]

Description

Rewards need a visible place in the user app to strengthen retention and demo impact.

Scope

• Add rewards route and navigation entry
• Display balance, recent earning events, and claim CTA
• Handle claim pending, success, and failure states

Acceptance Criteria

• User can view current balance and history on mobile
• Claim action is available from the rewards screen
• API failures and empty states are handled cleanly

Dependencies

Blocked by: #128

Stack

React Native / Express / Stellar

[kingdavid0016]

@kingdavid0016 has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

I'll like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @kingdavid0016 to this issue.