feat: add admin sales statistics dashboard with 5 analytics tabs

- Add sales stats API client with typed interfaces for all endpoints
- Implement AdminSalesStats page with summary cards and period selector
- Add TrialsTab with provider breakdown donut chart and daily area chart
- Add SalesTab with tariff/period breakdown and daily revenue chart
- Add RenewalsTab with period comparison and trend indicators
- Add AddonsTab with package breakdown bar chart
- Add DepositsTab with payment method breakdown bar chart
- Add SimpleBarChart, SimpleAreaChart, DonutChart components
- Add PeriodSelector with preset periods and custom date range
- Full responsive design (mobile/tablet/desktop/TG Mini App)
- ARIA accessibility (tablist, tab, tabpanel, aria-selected)
- Error handling with isError on all queries
- Empty data guards on all chart components
- i18n support across all 4 locales (en, ru, zh, fa)

src/components/sales-stats/index.ts

@@ -0,0 +1,9 @@
+export { AddonsTab } from './AddonsTab';
+export { DepositsTab } from './DepositsTab';
+export { DonutChart } from './DonutChart';
+export { PeriodSelector } from './PeriodSelector';
+export { RenewalsTab } from './RenewalsTab';
+export { SalesTab } from './SalesTab';
+export { SimpleAreaChart } from './SimpleAreaChart';
+export { SimpleBarChart } from './SimpleBarChart';
+export { TrialsTab } from './TrialsTab';