feat: 为用户设备添加 DeviceNo 字段并实现 ID 混淆，同时在迁移脚本中新增 ID 重建逻辑。

pkg/tool/device.go

@@ -0,0 +1,25 @@
+package tool
+
+import (
+	"fmt"
+	"strings"
+)
+
+const deviceHashSalt uint32 = 0x5A3C7E9B
+
+// DeviceIdToHash encodes a device id to an 8-char uppercase hex string.
+// Algorithm mirrors frontend: id XOR salt → hex.
+// e.g. 1 → "5A3C7E9A", 42 → "5A3C7EA1"
+func DeviceIdToHash(id int64) string {
+	return strings.ToUpper(fmt.Sprintf("%08x", uint32(id)^deviceHashSalt))
+}
+
+// HashToDeviceId decodes an 8-char hex hash back to a device id.
+func HashToDeviceId(hash string) (int64, error) {
+	var n uint32
+	_, err := fmt.Sscanf(strings.ToLower(hash), "%08x", &n)
+	if err != nil {
+		return 0, err
+	}
+	return int64(n ^ deviceHashSalt), nil
+}