revert: remove user-facing reset traffic toggle

Reset traffic on tariff switch is an admin-only setting.
Backend handles it via admin settings system (data-driven, no frontend code needed).
Reverted all user-facing toggle UI, API params, types, and translations.

src/locales/zh.json

@@ -378,9 +378,7 @@
       "remainingDays": "剩余天数",
       "switch": "切换",
       "title": "切换套餐",
-      "upgradeCost": "升级费用",
-      "resetTraffic": "重置流量",
-      "resetTrafficHint": "切换套餐时重置已使用流量"
+      "upgradeCost": "升级费用"
     },
     "promoGroup": {
       "yourGroup": "您的组：{{name}}",