feat: add stream health, optimistic updates, pull-to-refresh, and PWA offline support

[zane1502]

Summary

Resolves all assigned issues for stream health indicators, optimistic UI updates, mobile pull-to-refresh gesture, and PWA install prompt / offline fallback support.

Changes

• Stream Health Indicator (Add stream health status indicator showing time remaining and flow rate on detail page #230): Added StreamHealthCard with real-time countdown, friendly flow rates, progress bar, settled amounts, and refunds.
• Optimistic UI Updates (Implement optimistic UI updates so stream list reflects changes before confirmation #231): Implemented optimistic updates for stream actions with Confirming indicator, rollbacks on failure, and E2E tests.
• Pull-to-Refresh Gesture (Add pull-to-refresh gesture on the dashboard stream list for mobile users #232): Added touch PullToRefresh component with 60px threshold and mobile support.
• PWA Support (Add PWA install prompt and offline fallback page #233): Added visit-based install banner, offline fallback page, service worker precaching, and app icons.

Issues

Resolves #230
Resolves #231
Resolves #232
Resolves #233

Verification

• Manual code review completed.
• cargo build was not run.
• cargo test was not run.
• No snapshots were committed.

[drips-wave]

@zane1502 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits

[vercel]

@zane1502 is attempting to deploy a commit to the Chuks7 Team on Vercel.

A member of the Team first needs to authorize it.