fix(ops): 统一 request-errors 和 SLA 的错误分类逻辑

修复 request-errors 接口与 Dashboard Overview SLA 计算不一致的问题：
- errors 视图现在只排除业务限制错误（余额不足、并发限制等）
- 上游 429/529 错误现在包含在 errors 视图中，与 SLA 计算保持一致
- excluded 视图现在只显示业务限制错误

这确保了 request-errors 接口和 Dashboard 的 error_count_sla 使用相同的过滤逻辑。

backend/internal/repository/ops_repo.go

@@ -992,7 +992,8 @@ func buildOpsErrorLogsWhere(filter *service.OpsErrorLogFilter) (string, []any) {
 	}
 
 	// View filter: errors vs excluded vs all.
-	// Excluded = upstream 429/529 and business-limited (quota/concurrency/billing) errors.
+	// Excluded = business-limited errors (quota/concurrency/billing).
+	// Upstream 429/529 are included in errors view to match SLA calculation.
 	view := ""
 	if filter != nil {
 		view = strings.ToLower(strings.TrimSpace(filter.View))
@@ -1000,15 +1001,13 @@ func buildOpsErrorLogsWhere(filter *service.OpsErrorLogFilter) (string, []any) {
 	switch view {
 	case "", "errors":
 		clauses = append(clauses, "COALESCE(is_business_limited,false) = false")
-		clauses = append(clauses, "COALESCE(upstream_status_code, status_code, 0) NOT IN (429, 529)")
 	case "excluded":
-		clauses = append(clauses, "(COALESCE(is_business_limited,false) = true OR COALESCE(upstream_status_code, status_code, 0) IN (429, 529))")
+		clauses = append(clauses, "COALESCE(is_business_limited,false) = true")
 	case "all":
 		// no-op
 	default:
 		// treat unknown as default 'errors'
 		clauses = append(clauses, "COALESCE(is_business_limited,false) = false")
-		clauses = append(clauses, "COALESCE(upstream_status_code, status_code, 0) NOT IN (429, 529)")
 	}
 	if len(filter.StatusCodes) > 0 {
 		args = append(args, pq.Array(filter.StatusCodes))