feat(PrizePool): add currency toggle for multi-currency tables

[Eetwalt]

Summary

Based on #7688

• Replace the prize pool's side-by-side currency columns with a pill toggle that shows one currency's money columns at a time
• Extract a reusable Widget/ContentSwitch/Pill widget from ContentSwitch (output byte-identical for existing consumers)
• Tag each money header/cell with data-toggle-area-content and reuse the global togglearea JS + .toggle-area CSS — no new JS or mechanism CSS
• Default to the first local currency; single-currency and award tables render no toggle; multiple prize pools on one page toggle independently

How did you test this change?

dev + devtools

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