feat: add enrichment columns to admin traffic usage table

Add 5 new columns (connected devices, spending, start/end dates, last node)
with progressive loading shimmer placeholders and 4-language translations.

src/locales/en.json

@@ -822,7 +822,12 @@
       "riskLow": "Low",
       "riskMedium": "Medium",
       "riskHigh": "High",
-      "riskCritical": "Critical"
+      "riskCritical": "Critical",
+      "connected": "Conn.",
+      "totalSpent": "Spent",
+      "subStart": "Start",
+      "subEnd": "End",
+      "lastNode": "Last Node"
     },
     "emailTemplates": {
       "title": "Email Templates",

src/locales/fa.json

@@ -1,4 +1,4 @@
-{
+{
   "common": {
     "loading": "در حال بارگذاری...",
     "all": "همه",
@@ -703,7 +703,12 @@
       "riskLow": "کم",
       "riskMedium": "متوسط",
       "riskHigh": "بالا",
-      "riskCritical": "بحرانی"
+      "riskCritical": "بحرانی",
+      "connected": "متصل",
+      "totalSpent": "هزینه",
+      "subStart": "شروع",
+      "subEnd": "پایان",
+      "lastNode": "آخرین نود"
     },
     "emailTemplates": {
       "title": "قالب‌های ایمیل",

src/locales/ru.json

@@ -1,4 +1,4 @@
-{
+{
   "common": {
     "all": "Все",
     "loading": "Загрузка...",
@@ -843,7 +843,12 @@
       "riskLow": "Низкий",
       "riskMedium": "Средний",
       "riskHigh": "Высокий",
-      "riskCritical": "Критический"
+      "riskCritical": "Критический",
+      "connected": "Подкл.",
+      "totalSpent": "Траты",
+      "subStart": "Начало",
+      "subEnd": "Конец",
+      "lastNode": "Посл. нода"
     },
     "emailTemplates": {
       "title": "Email-шаблоны",

src/locales/zh.json

@@ -1,4 +1,4 @@
-{
+{
   "common": {
     "loading": "加载中...",
     "error": "错误",
@@ -703,7 +703,12 @@
       "riskLow": "低",
       "riskMedium": "中",
       "riskHigh": "高",
-      "riskCritical": "严重"
+      "riskCritical": "严重",
+      "connected": "连接",
+      "totalSpent": "消费",
+      "subStart": "开始",
+      "subEnd": "结束",
+      "lastNode": "最近节点"
     },
     "paymentMethods": {
       "title": "支付方法",