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.
- 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)
- Add discount fields to TrafficPackage and TariffSwitchPreview types
- Show strikethrough original price and discount badge for device purchase
- Show discount badge and original price for traffic packages
- Show discount info and free label for tariff switch with 100% discount