fix(ops): 修复告警状态验证和错误处理逻辑

- 增强告警事件状态验证，添加合法状态值检查
- 移除重试逻辑中的遗留字段赋值
- 修正仓库不可用时的错误类型
- 格式化测试文件代码

backend/internal/service/ops_alert_evaluator_service.go

@@ -206,7 +206,7 @@ func (s *OpsAlertEvaluatorService) evaluateOnce(interval time.Duration) {
 			continue
 		}
 
-		scopePlatform, scopeGroupID := parseOpsAlertRuleScope(rule.Filters)
+		scopePlatform, scopeGroupID, scopeRegion := parseOpsAlertRuleScope(rule.Filters)
 
 		windowMinutes := rule.WindowMinutes
 		if windowMinutes <= 0 {
@@ -239,7 +239,7 @@ func (s *OpsAlertEvaluatorService) evaluateOnce(interval time.Duration) {
 			// Scoped silencing: if a matching silence exists, skip creating a firing event.
 			if s.opsService != nil {
 				platform := strings.TrimSpace(scopePlatform)
-				region := (*string)(nil)
+				region := scopeRegion
 				if platform != "" {
 					if ok, err := s.opsService.IsAlertSilenced(ctx, rule.ID, platform, scopeGroupID, region, now); err == nil && ok {
 						continue
@@ -370,9 +370,9 @@ func requiredSustainedBreaches(sustainedMinutes int, interval time.Duration) int
 	return required
 }
 
-func parseOpsAlertRuleScope(filters map[string]any) (platform string, groupID *int64) {
+func parseOpsAlertRuleScope(filters map[string]any) (platform string, groupID *int64, region *string) {
 	if filters == nil {
-		return "", nil
+		return "", nil, nil
 	}
 	if v, ok := filters["platform"]; ok {
 		if s, ok := v.(string); ok {
@@ -403,7 +403,15 @@ func parseOpsAlertRuleScope(filters map[string]any) (platform string, groupID *i
 			}
 		}
 	}
-	return platform, groupID
+	if v, ok := filters["region"]; ok {
+		if s, ok := v.(string); ok {
+			vv := strings.TrimSpace(s)
+			if vv != "" {
+				region = &vv
+			}
+		}
+	}
+	return platform, groupID, region
 }
 
 func (s *OpsAlertEvaluatorService) computeRuleMetric(