fix: unify wheel Stars payment across desktop and mobile

- Use Telegram Stars invoice on all platforms instead of balance
  payment on desktop
- Show star cost in toggle and subtitle everywhere
- Show popup/toast when Stars are not enabled and user tries to spin
- Remove platform-specific payment type auto-select logic
- Add starsNotAvailable translation key (ru, en, zh, fa)

src/locales/zh.json

@@ -603,6 +603,7 @@
     "starsPaymentSuccess": "支付成功！抽奖结果已发送到Telegram。",
     "starsPaymentFailed": "支付失败。请重试。",
     "starsPaymentRedirected": "将打开Telegram进行支付。支付后请刷新页面。",
+    "starsNotAvailable": "星星支付暂不可用。请联系客服。",
     "noHistory": "暂无抽奖记录",
     "banner": {
       "title": "试试运气！",