refactor: consolidate icons and move server edit to separate page

- Create centralized icons file at src/components/icons/index.tsx
- Update admin and AppShell icons to re-export from centralized location
- Replace trial "T" button with GiftIcon in AdminServers
- Move server editing from modal to dedicated page /admin/servers/:id/edit
- Add localization keys for server edit page (mainSettings, pricingAndLimits, updateError)

src/locales/en.json

@@ -1382,7 +1382,10 @@
       "enable": "Enable",
       "disable": "Disable",
       "toggleTrial": "Toggle Trial",
-      "loadError": "Failed to load server"
+      "loadError": "Failed to load server",
+      "mainSettings": "Main Settings",
+      "pricingAndLimits": "Pricing & Limits",
+      "updateError": "Failed to save changes"
     },
     "campaigns": {
       "title": "Ad Campaigns",

src/locales/fa.json

@@ -1137,7 +1137,10 @@
       "enable": "فعال",
       "disable": "غیرفعال",
       "toggleTrial": "تغییر آزمایشی",
-      "loadError": "بارگذاری سرور ناموفق بود"
+      "loadError": "بارگذاری سرور ناموفق بود",
+      "mainSettings": "تنظیمات اصلی",
+      "pricingAndLimits": "قیمت‌گذاری و محدودیت‌ها",
+      "updateError": "ذخیره تغییرات ناموفق بود"
     },
     "paymentMethods": {
       "title": "روش‌های پرداخت",

src/locales/ru.json

@@ -1893,7 +1893,10 @@
       "enable": "Включить",
       "disable": "Отключить",
       "toggleTrial": "Переключить триал",
-      "loadError": "Не удалось загрузить сервер"
+      "loadError": "Не удалось загрузить сервер",
+      "mainSettings": "Основные настройки",
+      "pricingAndLimits": "Цены и лимиты",
+      "updateError": "Не удалось сохранить изменения"
     },
     "campaigns": {
       "title": "Рекламные кампании",

src/locales/zh.json

@@ -1174,7 +1174,10 @@
       "enable": "启用",
       "disable": "禁用",
       "toggleTrial": "切换试用",
-      "loadError": "加载服务器失败"
+      "loadError": "加载服务器失败",
+      "mainSettings": "基本设置",
+      "pricingAndLimits": "价格和限制",
+      "updateError": "保存更改失败"
     },
     "campaigns": {
       "title": "广告活动",