feat: add webhook notification service and refactor data management

## Backend Changes
- Add WebhookService for sending alert notifications via HTTP webhooks
- Implement HMAC-SHA256 signature for webhook payload authentication
- Add webhook configuration API endpoints and settings
- Integrate webhook calls into OpsAlertEvaluatorService
- Fix routes/common.go string conversion (use strconv.Itoa)
- Add comprehensive webhook service tests

## Frontend Changes
- Add webhook notification configuration UI in OpsSettingsDialog
- Add WebhookNotificationConfig types and API functions
- Add i18n translations for webhook features (zh/en)
- Refactor DataManagementView.vue into modular components:
  - PostgresProfilesCard.vue (356 lines)
  - RedisProfilesCard.vue (331 lines)
  - S3ProfilesCard.vue (363 lines)
  - BackupJobsCard.vue (216 lines)
  - DataManagementView.vue (94 lines)
- Add OpsSettingsDialog component tests

## Testing
- All backend tests pass
- All frontend tests pass
- Webhook service tests cover signature, HTTP, timeout, error handling

frontend/src/i18n/locales/zh.ts

@@ -4212,6 +4212,34 @@ export default {
           accountHealthThresholdRange: '账号健康错误率阈值必须在 0 到 100 之间'
         }
       },
+      webhookNotification: {
+        title: 'Webhook 通知配置',
+        description: '配置告警 Webhook 通知，支持集成企业 IM（钉钉、飞书、企业微信等）。',
+        loading: '加载中...',
+        loadFailed: '加载 Webhook 配置失败',
+        saveSuccess: 'Webhook 配置已保存',
+        saveFailed: '保存 Webhook 配置失败',
+        alertTitle: '告警 Webhook',
+        reportTitle: '报告 Webhook',
+        urls: 'Webhook URL',
+        urlsHint: '每行一个 URL，支持多个 Webhook',
+        secret: '签名密钥',
+        secretHint: '可选，用于生成 HMAC-SHA256 签名',
+        minSeverity: '最低级别',
+        minSeverityAll: '全部级别',
+        timeoutSeconds: '超时时间（秒）',
+        includeResolved: '包含恢复通知',
+        rateLimitPerHour: '每小时限额',
+        dailyReport: '每日报告',
+        validation: {
+          title: '请先修正以下问题',
+          invalid: 'Webhook 配置不合法',
+          urlsRequired: '已启用 Webhook，但未配置任何 URL',
+          invalidUrls: '存在不合法的 URL',
+          timeoutRange: '超时时间必须在 1 到 60 秒之间',
+          rateLimitRange: '每小时限额必须为 ≥ 0 的数字'
+        }
+      },
       settings: {
         title: '运维监控设置',
         loadFailed: '加载设置失败',