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

backend/internal/handler/admin/ops_settings_handler.go

@@ -56,6 +56,52 @@ func (h *OpsHandler) UpdateEmailNotificationConfig(c *gin.Context) {
 	response.Success(c, updated)
 }
 
+// GetWebhookNotificationConfig returns Ops webhook notification config (DB-backed).
+// GET /api/v1/admin/ops/webhook-notification/config
+func (h *OpsHandler) GetWebhookNotificationConfig(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	cfg, err := h.opsService.GetWebhookNotificationConfig(c.Request.Context())
+	if err != nil {
+		response.Error(c, http.StatusInternalServerError, "Failed to get webhook notification config")
+		return
+	}
+	response.Success(c, cfg)
+}
+
+// UpdateWebhookNotificationConfig updates Ops webhook notification config (DB-backed).
+// PUT /api/v1/admin/ops/webhook-notification/config
+func (h *OpsHandler) UpdateWebhookNotificationConfig(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	var req service.OpsWebhookNotificationConfigUpdateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request body")
+		return
+	}
+
+	updated, err := h.opsService.UpdateWebhookNotificationConfig(c.Request.Context(), &req)
+	if err != nil {
+		response.Error(c, http.StatusBadRequest, err.Error())
+		return
+	}
+	response.Success(c, updated)
+}
+
 // GetAlertRuntimeSettings returns Ops alert evaluator runtime settings (DB-backed).
 // GET /api/v1/admin/ops/runtime/alert
 func (h *OpsHandler) GetAlertRuntimeSettings(c *gin.Context) {