v1.2.1

What's changed

• New: public REST endpoint GET /nera-stw/v1/product/{id}/prizes returns physical and site-credit prize segments with availability counts, recent winners (privacy-masked), totals, a 60-second server-side cache, and per-IP rate limiting (30 req/min) — powers the new prize banner on single-product pages.
• New: site-credit (wallet) segments now support an optional stock cap in the product admin; leaving the field empty means unlimited, setting it to 0 marks the prize sold out.
• Fix: spin eligibility and stock decrement/rollback logic now apply to capped site-credit prizes the same way they apply to physical prizes.
• Fix: prize banner cache is automatically cleared when product segment settings are saved.