merge: production into main (resolve WinnersGrid conflict)

Production carried the pre-polish version of WinnersGrid; main has the
polished version from #580 (summary chip with completion state + total
pool, track-name chip on track cards, dropped "$X USDC" double-sign).
Five conflict regions, all resolved in favour of main since that's what
we want to ship to prod.

Result: PR #581 (main -> production) is now a clean fast-forward.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 0xdevcollins