feat: show subscription revenue and referral earnings in network stats

Add subscription revenue (total from subscription payments) to the
stats panel alongside referral earnings. Layout updated to 2-column
grid with subscription revenue highlighted in accent color.

src/locales/en.json

@@ -1247,7 +1247,8 @@
         "totalUsers": "Users",
         "totalReferrers": "Referrers",
         "totalCampaigns": "Campaigns",
-        "totalEarnings": "Total earnings"
+        "subscriptionRevenue": "Subscription revenue",
+        "totalEarnings": "Ref. earnings"
       },
       "legend": {
         "title": "Legend",

src/locales/fa.json

@@ -1081,7 +1081,8 @@
         "totalUsers": "کاربران",
         "totalReferrers": "ارجاع‌دهندگان",
         "totalCampaigns": "کمپین‌ها",
-        "totalEarnings": "درآمد کل"
+        "subscriptionRevenue": "درآمد اشتراک",
+        "totalEarnings": "درآمد ارجاع"
       },
       "legend": {
         "title": "راهنما",

src/locales/ru.json

@@ -1268,7 +1268,8 @@
         "totalUsers": "Пользователей",
         "totalReferrers": "Рефереров",
         "totalCampaigns": "Кампаний",
-        "totalEarnings": "Общий доход"
+        "subscriptionRevenue": "Доход с подписок",
+        "totalEarnings": "Реф. доход"
       },
       "legend": {
         "title": "Легенда",

src/locales/zh.json

@@ -1081,7 +1081,8 @@
         "totalUsers": "用户",
         "totalReferrers": "推荐人",
         "totalCampaigns": "活动",
-        "totalEarnings": "总收入"
+        "subscriptionRevenue": "订阅收入",
+        "totalEarnings": "推荐收入"
       },
       "legend": {
         "title": "图例",