feat(pkg/util): 补齐版本比较、网络与格式化通用助手

下游 OpenFlare 的边缘守护进程与发布流程需要这些与业务无关的纯函数，
按上游/下游归属规约回流到平台层，避免下游在上游目录里长期携带本地文件：

- version / version_compare：CompareVersions、ParseVersionInfo（版本区间比较）
- network：GetIP、IsPrivateIPv4
- format / value / string / slice：Bytes2Size、Seconds2Time、Interface2String、
  TrimStringFields、UniqueAndCleanStringSlice 与 IdentifiableTimeRecord

验证：go build 通过；go test ./... exit 0（48 包 ok）；
check_cordis_architecture.sh 0 violations；golangci-lint 0 issues；gofmt 干净。

backend/pkg/util/slice.go

@@ -0,0 +1,79 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package util
+
+import (
+	"sort"
+	"strings"
+	"time"
+)
+
+// Unique returns a new slice containing only the unique elements of the input slice,
+// preserving their original order.
+func Unique[T comparable](slice []T) []T {
+	if slice == nil {
+		return nil
+	}
+	seen := make(map[T]struct{})
+	result := make([]T, 0)
+	for _, item := range slice {
+		if _, ok := seen[item]; ok {
+			continue
+		}
+		seen[item] = struct{}{}
+		result = append(result, item)
+	}
+	return result
+}
+
+// UniqueAndCleanStringSlice trims spaces, removes empty elements, and returns only the unique elements
+// of the input string slice. It preserves order and returns nil if the resulting slice is empty.
+func UniqueAndCleanStringSlice(slice []string) []string {
+	if slice == nil {
+		return nil
+	}
+	seen := make(map[string]struct{})
+	result := make([]string, 0)
+	for _, item := range slice {
+		trimmed := strings.TrimSpace(item)
+		if trimmed == "" {
+			continue
+		}
+		if _, ok := seen[trimmed]; ok {
+			continue
+		}
+		seen[trimmed] = struct{}{}
+		result = append(result, trimmed)
+	}
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// IdentifiableTimeRecord represents a database record that has a unique ID and a primary timestamp field.
+type IdentifiableTimeRecord interface {
+	GetID() uint
+	GetTime() time.Time
+}
+
+// SortAndLimitRecords sorts a slice of IdentifiableTimeRecord descendingly by their timestamp (and ID as a tie-breaker),
+// and limits the slice to the specified size if limit > 0.
+func SortAndLimitRecords[T IdentifiableTimeRecord](rows []T, limit int) []T {
+	if len(rows) == 0 {
+		return rows
+	}
+	sort.Slice(rows, func(i, j int) bool {
+		ti := rows[i].GetTime()
+		tj := rows[j].GetTime()
+		if ti.Equal(tj) {
+			return rows[i].GetID() > rows[j].GetID()
+		}
+		return ti.After(tj)
+	})
+	if limit > 0 && len(rows) > limit {
+		rows = rows[:limit]
+	}
+	return rows
+}