feat(memory): add memory threshold alerts (#5366)

* feat(memory): add memory threshold alerts

Add memory (RAM) threshold alerts following the same architecture as
CPU alerts: CheckMemJob with @every 1m cadence, memoryAlarmWanted gate,
tgMemory/smtpMemory per-subscriber settings (default 80%), EventBusCheckboxes
with inline threshold input, i18n for en-US/ru-RU with English defaults.

# Conflicts:
#	internal/web/translation/ar-EG.json
#	internal/web/translation/es-ES.json
#	internal/web/translation/fa-IR.json
#	internal/web/translation/id-ID.json
#	internal/web/translation/ja-JP.json
#	internal/web/translation/pt-BR.json
#	internal/web/translation/ru-RU.json
#	internal/web/translation/tr-TR.json
#	internal/web/translation/uk-UA.json
#	internal/web/translation/vi-VN.json
#	internal/web/translation/zh-CN.json
#	internal/web/translation/zh-TW.json

* fix: address code review findings for memory alerts

- Remove dead settingService field from CheckMemJob
- Fix cpuThreshold double-emoji in 12 locale files (code prepends 🔴)
- Align TgCpu/TgMemory fields in entity.go
- Add missing SetTgMemory function

* fix: restore settingService in CheckMemJob for consistency with CheckCpuJob

frontend/src/components/ui/notifications/EmailNotifications.tsx

@@ -41,6 +41,14 @@ const GROUPS: NotificationGroupConfig[] = [
           <InputNumber size="small" min={0} max={100} value={value} onChange={onChange} style={{ width: 80 }} />
         ),
       },
+      {
+        key: 'memory.high',
+        label: 'eventMemoryHigh',
+        settingKey: 'smtpMemory',
+        extra: ({ value, onChange }) => (
+          <InputNumber size="small" min={0} max={100} value={value} onChange={onChange} style={{ width: 80 }} />
+        ),
+      },
     ],
   },
   {

frontend/src/components/ui/notifications/TelegramNotifications.tsx

@@ -41,6 +41,14 @@ const GROUPS: NotificationGroupConfig[] = [
           <InputNumber size="small" min={0} max={100} value={value} onChange={onChange} style={{ width: 80 }} />
         ),
       },
+      {
+        key: 'memory.high',
+        label: 'eventMemoryHigh',
+        settingKey: 'tgMemory',
+        extra: ({ value, onChange }) => (
+          <InputNumber size="small" min={0} max={100} value={value} onChange={onChange} style={{ width: 80 }} />
+        ),
+      },
     ],
   },
   {