feat: add reset traffic toggle on tariff switch

- Add reset_traffic parameter to previewTariffSwitch and switchTariff API calls
- Add reset_traffic_available/reset_traffic_default fields to TariffSwitchPreview type
- Add toggle switch in tariff switch preview modal (shown when backend enables it)
- Initialize toggle from server default (reset_traffic_default)
- Pass reset_traffic flag on switch execution
- Add translations for all 4 locales (ru, en, zh, fa)

src/locales/fa.json

@@ -378,7 +378,9 @@
       "remainingDays": "روزهای باقی‌مانده",
       "switch": "تغییر",
       "title": "تغییر تعرفه",
-      "upgradeCost": "هزینه ارتقا"
+      "upgradeCost": "هزینه ارتقا",
+      "resetTraffic": "بازنشانی ترافیک",
+      "resetTrafficHint": "بازنشانی ترافیک مصرفی هنگام تغییر تعرفه"
     },
     "promoGroup": {
       "yourGroup": "گروه شما: {{name}}",