refactor(pkg): merge pkg/utils into pkg/util

Consolidate pure helper packages under pkg/util and update imports.

pkg/util/network.go

@@ -0,0 +1,42 @@
+package util
+
+import (
+	"log/slog"
+	"net"
+)
+
+// GetIP returns the first private IPv4 address found on the local network interfaces.
+func GetIP() (ip string) {
+	ips, err := net.InterfaceAddrs()
+	if err != nil {
+		slog.Error("get interface addresses failed", "error", err)
+		return ip
+	}
+
+	for _, a := range ips {
+		if candidate, ok := privateIPv4FromAddr(a); ok {
+			return candidate
+		}
+	}
+	return
+}
+
+func privateIPv4FromAddr(addr net.Addr) (string, bool) {
+	ipNet, ok := addr.(*net.IPNet)
+	if !ok || ipNet.IP.IsLoopback() || ipNet.IP.To4() == nil {
+		return "", false
+	}
+	ip := ipNet.IP.String()
+	if isPrivateIPv4(ip) {
+		return ip, true
+	}
+	return "", false
+}
+
+func isPrivateIPv4(ip string) bool {
+	parsedIP := net.ParseIP(ip)
+	if parsedIP == nil {
+		return false
+	}
+	return parsedIP.IsPrivate()
+}