feat: enhance sales stats with device stats, per-tariff charts, and dual-series trials

- Add DualAreaChart component for two-series visualization (registrations vs trials)
- Add MultiSeriesAreaChart component for N-series tariff breakdown with dynamic pivoting
- AddonsTab: add device purchases and device revenue stat cards
- SalesTab: add per-tariff daily sales chart using MultiSeriesAreaChart
- TrialsTab: replace single-series area chart with dual-series registrations + trials chart
- Update TypeScript interfaces to match backend schema changes
- Add i18n keys for all new UI elements across en, ru, zh, fa locales

src/locales/en.json

@@ -1106,10 +1106,12 @@
       },
       "trials": {
         "total": "Total Trials",
+        "totalRegistrations": "Registrations",
+        "trialsIssued": "Trials Issued",
         "conversion": "Conversion Rate",
         "avgDuration": "Avg Duration",
         "byProvider": "By Registration Source",
-        "dailyChart": "Daily Registrations",
+        "dailyChart": "Daily Registrations & Trials",
         "registrations": "Registrations"
       },
       "sales": {
@@ -1118,7 +1120,9 @@
         "topTariff": "Top Tariff",
         "byTariff": "Sales by Tariff",
         "byPeriod": "By Subscription Period",
-        "dailyChart": "Daily Sales"
+        "dailyChart": "Daily Sales",
+        "dailyByTariff": "Sales by Tariff per Day",
+        "subscriptions": "Subscriptions"
       },
       "renewals": {
         "total": "Total Renewals",
@@ -1134,6 +1138,8 @@
         "totalPurchases": "Total Purchases",
         "totalGb": "Total Traffic",
         "revenue": "Revenue",
+        "devicePurchases": "Device Purchases",
+        "deviceRevenue": "Device Revenue",
         "byPackage": "By Package Size",
         "dailyChart": "Daily Purchases",
         "purchases": "Purchases"

src/locales/fa.json

@@ -929,10 +929,12 @@
       },
       "trials": {
         "total": "کل آزمایشی",
+        "totalRegistrations": "ثبت‌نام‌ها",
+        "trialsIssued": "آزمایشی صادرشده",
         "conversion": "نرخ تبدیل",
         "avgDuration": "میانگین مدت",
         "byProvider": "بر اساس منبع",
-        "dailyChart": "ثبت‌نام روزانه",
+        "dailyChart": "ثبت‌نام و آزمایشی روزانه",
         "registrations": "ثبت‌نام"
       },
       "sales": {
@@ -941,7 +943,9 @@
         "topTariff": "تعرفه برتر",
         "byTariff": "بر اساس تعرفه",
         "byPeriod": "بر اساس دوره",
-        "dailyChart": "فروش روزانه"
+        "dailyChart": "فروش روزانه",
+        "dailyByTariff": "فروش روزانه بر اساس تعرفه",
+        "subscriptions": "اشتراک‌ها"
       },
       "renewals": {
         "total": "کل تمدیدها",
@@ -957,6 +961,8 @@
         "totalPurchases": "کل خرید",
         "totalGb": "کل ترافیک",
         "revenue": "درآمد",
+        "devicePurchases": "خرید دستگاه",
+        "deviceRevenue": "درآمد دستگاه",
         "byPackage": "بر اساس بسته",
         "dailyChart": "خرید روزانه",
         "purchases": "خرید"

src/locales/ru.json

@@ -1127,10 +1127,12 @@
       },
       "trials": {
         "total": "Всего триалов",
+        "totalRegistrations": "Регистрации",
+        "trialsIssued": "Выданные триалы",
         "conversion": "Конверсия",
         "avgDuration": "Средняя длит.",
         "byProvider": "По источнику регистрации",
-        "dailyChart": "Регистрации по дням",
+        "dailyChart": "Регистрации и триалы по дням",
         "registrations": "Регистрации"
       },
       "sales": {
@@ -1139,7 +1141,9 @@
         "topTariff": "Топ тариф",
         "byTariff": "Продажи по тарифам",
         "byPeriod": "По периоду подписки",
-        "dailyChart": "Продажи по дням"
+        "dailyChart": "Продажи по дням",
+        "dailyByTariff": "Продажи по тарифам по дням",
+        "subscriptions": "Подписки"
       },
       "renewals": {
         "total": "Всего продлений",
@@ -1155,6 +1159,8 @@
         "totalPurchases": "Всего покупок",
         "totalGb": "Всего трафика",
         "revenue": "Доход",
+        "devicePurchases": "Покупки устройств",
+        "deviceRevenue": "Доход от устройств",
         "byPackage": "По размеру пакета",
         "dailyChart": "Покупки по дням",
         "purchases": "Покупки"

src/locales/zh.json

@@ -929,10 +929,12 @@
       },
       "trials": {
         "total": "试用总数",
+        "totalRegistrations": "注册数",
+        "trialsIssued": "已发放试用",
         "conversion": "转化率",
         "avgDuration": "平均时长",
         "byProvider": "按注册来源",
-        "dailyChart": "每日注册",
+        "dailyChart": "每日注册与试用",
         "registrations": "注册"
       },
       "sales": {
@@ -941,7 +943,9 @@
         "topTariff": "热门套餐",
         "byTariff": "按套餐",
         "byPeriod": "按订阅周期",
-        "dailyChart": "每日销售"
+        "dailyChart": "每日销售",
+        "dailyByTariff": "每日按套餐销售",
+        "subscriptions": "订阅"
       },
       "renewals": {
         "total": "续订总数",
@@ -957,6 +961,8 @@
         "totalPurchases": "购买总数",
         "totalGb": "总流量",
         "revenue": "收入",
+        "devicePurchases": "设备购买",
+        "deviceRevenue": "设备收入",
         "byPackage": "按套餐大小",
         "dailyChart": "每日购买",
         "purchases": "购买"