feat(arp): 自 go-hua 迁入 ARP 表查询与定时刷新缓存

- IP→MAC 查询(AutoRefresh 后台刷新/Search/Table), 新增依赖 mostlygeek/arp
- 附测试、examples/arp 例程与包 README

arp/arp_windows.go

@@ -0,0 +1,57 @@
+//go:build windows
+// +build windows
+
+package arp
+
+// Windows arp table reader added by Claudio Matsuoka.
+// Tested only in Windows 8.1, hopefully the arp command output format
+// is the same in other Windows versions.
+
+import (
+	"os/exec"
+	"strings"
+	"syscall"
+)
+
+// Table 读取 Windows 系统 ARP 表（执行 arp -a 命令解析）
+// MAC 地址统一转换为冒号分隔格式
+func Table() ArpTable {
+	cmd := exec.Command("arp", "-a")
+	// 隐藏窗口
+	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+	data, err := cmd.Output()
+	// data, err := exec.Command("arp", "-a").Output()
+	if err != nil {
+		return nil
+	}
+
+	var table = make(ArpTable)
+	skipNext := false
+	for _, line := range strings.Split(string(data), "\n") {
+		// skip empty lines
+		if len(line) <= 0 {
+			continue
+		}
+		// skip Interface: lines
+		if line[0] != ' ' {
+			skipNext = true
+			continue
+		}
+		// skip column headers
+		if skipNext {
+			skipNext = false
+			continue
+		}
+
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+
+		ip := fields[0]
+		// Normalize MAC address to colon-separated format
+		table[ip] = strings.Replace(fields[1], "-", ":", -1)
+	}
+
+	return table
+}