Committed as acc6383 on main. The working tree is clean.

What was built

• Reward receipt viewer, a Vite + React + TypeScript single page. Paste a JSON array of receipts, and it validates every field, collapses duplicates on chainId + txHash + logIndex, hides Sepolia (11155111) by default, sums per-token totals with BigInt, and exports the shown rows as JSON or CSV. State persists in localStorage, so a refresh restores the same view.
• Mock sample with the required cases: two transfers in one transaction, one exact duplicate, one Sepolia transfer, and a raw value of 123456789012345678901234567 that stays exact. A "Mock data" badge, the status line and the export flag all label it.
• Wording calls every row an observed transfer, not a proven reward. No wallet, signatures, or transactions anywhere.
• Deliverables: src/, package.json + lockfile, committed dist/ with ./assets/... URLs, README.md (install, preview, rebuild, publish), DESIGN.md (tokens, typography, components, breakpoint), TESTING.md (test report and Better Interface review, identical copy at artifacts/validation.md), and seven screenshots under artifacts/screenshots/.

Checks that ran on the final source

Check	Result
tsc --noEmit	exit 0
vitest run	20 passed
vite build	exit 0, 68 kB gzipped JS
Playwright script against served dist/	82/82 at 1280, 390 and 320 px

The browser script covered empty, sample, filter-empty and error states, both downloads, refresh persistence including a filter override, clear with confirmation, a keyboard walk with visible focus rings at every stop, and zero console or resource failures.

Better Interface findings fixed

1. Focus ring would have been invisible on the filled primary button (same blue). Fixed with a 2px outline offset onto the surrounding surface.
2. Control border measured 1.88:1, below the 3:1 non-text floor. Replaced with a darker step at 3.12:1.
3. Borderless "Clear receipts" and "Reset chains" read as text on mobile. Both now use the standard bordered button.

Limitations recorded

The MCP browser tool had no managed preview server in this environment, and module scripts do not load over file://, so rendered checks ran through the Playwright library against the same Chromium build in one bounded script. Screen-reader sessions, automated accessibility audits, native zoom, forced-colors rendering and physical devices were not tested. A write to .npmrc was declined and is not needed.