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/api/adminSalesStats.ts

@@ -0,0 +1,175 @@
+import apiClient from './client';
+
+// ============ Period Params ============
+
+export interface SalesStatsParams {
+  days?: number;
+  start_date?: string;
+  end_date?: string;
+}
+
+// ============ Summary ============
+
+export interface SalesSummary {
+  total_revenue_kopeks: number;
+  active_subscriptions: number;
+  active_trials: number;
+  new_trials: number;
+  trial_to_paid_conversion: number;
+  renewals_count: number;
+  addon_revenue_kopeks: number;
+}
+
+// ============ Trials ============
+
+export interface ProviderBreakdownItem {
+  provider: string;
+  count: number;
+}
+
+export interface DailyTrialItem {
+  date: string;
+  count: number;
+}
+
+export interface TrialsStats {
+  total_trials: number;
+  conversion_rate: number;
+  avg_trial_duration_days: number;
+  by_provider: ProviderBreakdownItem[];
+  daily: DailyTrialItem[];
+}
+
+// ============ Sales ============
+
+export interface SalesByTariffItem {
+  tariff_id: number;
+  tariff_name: string;
+  count: number;
+}
+
+export interface SalesByPeriodItem {
+  period_days: number;
+  count: number;
+}
+
+export interface DailySalesItem {
+  date: string;
+  count: number;
+  revenue_kopeks: number;
+}
+
+export interface SalesStats {
+  total_sales: number;
+  total_revenue_kopeks: number;
+  avg_order_kopeks: number;
+  top_tariff_name: string;
+  by_tariff: SalesByTariffItem[];
+  by_period: SalesByPeriodItem[];
+  daily: DailySalesItem[];
+}
+
+// ============ Renewals ============
+
+export interface RenewalPeriodStats {
+  count: number;
+  revenue_kopeks: number;
+}
+
+export interface RenewalChange {
+  absolute: number;
+  percent: number;
+  trend: 'up' | 'down' | 'stable';
+}
+
+export interface DailyRenewalItem {
+  date: string;
+  count: number;
+}
+
+export interface RenewalsStats {
+  total_renewals: number;
+  total_revenue_kopeks: number;
+  renewal_rate: number;
+  current_period: RenewalPeriodStats;
+  previous_period: RenewalPeriodStats;
+  change: RenewalChange;
+  daily: DailyRenewalItem[];
+}
+
+// ============ Add-ons ============
+
+export interface AddonByPackageItem {
+  traffic_gb: number;
+  count: number;
+}
+
+export interface DailyAddonItem {
+  date: string;
+  count: number;
+  total_gb: number;
+}
+
+export interface AddonsStats {
+  total_purchases: number;
+  total_gb_purchased: number;
+  addon_revenue_kopeks: number;
+  by_package: AddonByPackageItem[];
+  daily: DailyAddonItem[];
+}
+
+// ============ Deposits ============
+
+export interface DepositByMethodItem {
+  method: string;
+  count: number;
+  amount_kopeks: number;
+}
+
+export interface DailyDepositItem {
+  date: string;
+  count: number;
+  amount_kopeks: number;
+}
+
+export interface DepositsStats {
+  total_deposits: number;
+  total_amount_kopeks: number;
+  avg_deposit_kopeks: number;
+  by_method: DepositByMethodItem[];
+  daily: DailyDepositItem[];
+}
+
+// ============ API ============
+
+export const salesStatsApi = {
+  getSummary: async (params: SalesStatsParams = {}): Promise<SalesSummary> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/summary', { params });
+    return response.data;
+  },
+
+  getTrials: async (params: SalesStatsParams = {}): Promise<TrialsStats> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/trials', { params });
+    return response.data;
+  },
+
+  getSales: async (params: SalesStatsParams = {}): Promise<SalesStats> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/subscriptions', { params });
+    return response.data;
+  },
+
+  getRenewals: async (params: SalesStatsParams = {}): Promise<RenewalsStats> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/renewals', { params });
+    return response.data;
+  },
+
+  getAddons: async (params: SalesStatsParams = {}): Promise<AddonsStats> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/addons', { params });
+    return response.data;
+  },
+
+  getDeposits: async (params: SalesStatsParams = {}): Promise<DepositsStats> => {
+    const response = await apiClient.get('/cabinet/admin/stats/sales/deposits', { params });
+    return response.data;
+  },
+};