PWA: Implement Service Worker for Offline-First Payments

[Smartdevs17]

Description\nImplement Service Worker infrastructure for offline-capable PWA. Allow payment queue creation offline with automatic sync when connected.\n\nCurrent Limitation: No offline support.\nExpected Outcome: Offline payment queue with automatic sync, conflict resolution, and offline indicator.\n## Acceptance Criteria\n- [ ] Service worker setup\n- [ ] Offline detection\n- [ ] Payment queue in IndexedDB\n- [ ] Automatic sync on reconnect\n- [ ] Conflict resolution\n- [ ] Sync status indicator\n- [ ] Offline analytics\n- [ ] Background sync registration\n## Technical Scope\n- Files: frontend/sw, offline logic\n- Edge Cases: Duplicate payments, network race conditions\n## Complexity Estimate\n200 points - Service worker, sync, offline.

[Ebuka321]

@Ebuka321 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

can i work on these

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[drips-wave]

Congratulations, @Ebuka321! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

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[drips-wave]

This issue has been completed by @Ebuka321 as part of the Stellar Wave Program's 4th Wave 🥳

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