fix(link): keep IPv6 brackets in imported wireguard endpoints (#6976)

parseWireguard joined u.Hostname(), which strips IPv6 brackets, with the port, so wireguard://key@[2001:db8::1]:51820 became 2001:db8::1:51820 and Xray's ParseDestination rejected it. The endpoint is now built with net.JoinHostPort, matching the frontend parser; IPv4 and hostname endpoints are unchanged.

internal/util/link/outbound.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"maps"
 	"math"
+	"net"
 	"net/url"
 	"regexp"
 	"slices"
@@ -657,7 +658,7 @@ func parseWireguard(link string) (*ParseResult, error) {
 	portStr := u.Port()
 	endpoint := host
 	if portStr != "" {
-		endpoint = host + ":" + portStr
+		endpoint = net.JoinHostPort(host, portStr)
 	}
 
 	addrRaw := firstParam(params, "address", "ip")

internal/util/link/outbound_helpers_test.go

@@ -431,6 +431,28 @@ func TestParse_VmessFinalMask(t *testing.T) {
 	}
 }
 
+func TestParseWireguard_Endpoint(t *testing.T) {
+	cases := []struct {
+		link string
+		want string
+	}{
+		{"wireguard://key@a.com:51820?publickey=pub#x", "a.com:51820"},
+		{"wireguard://key@1.2.3.4:51820?publickey=pub#x", "1.2.3.4:51820"},
+		{"wireguard://key@[2001:db8::1]:51820?publickey=pub#x", "[2001:db8::1]:51820"},
+		{"wireguard://key@a.com?publickey=pub#x", "a.com"},
+	}
+	for _, c := range cases {
+		res, err := ParseLink(c.link)
+		if err != nil {
+			t.Fatalf("parse %s: %v", c.link, err)
+		}
+		peer := res.Outbound["settings"].(map[string]any)["peers"].([]any)[0].(map[string]any)
+		if peer["endpoint"] != c.want {
+			t.Errorf("%s: endpoint = %v, want %q", c.link, peer["endpoint"], c.want)
+		}
+	}
+}
+
 func TestParse_RemarkDecodedOnce(t *testing.T) {
 	// Remarks as the subscription server writes them (encodeURIComponent).
 	cases := []struct {