fix(security): SSRF-guard node and remote HTTP clients

The Node.Probe and Remote.do paths built outbound URLs by string-
formatting admin-controlled fields (Scheme/Address/Port/BasePath)
straight into requests, then dialed the result with the default
transport. CodeQL flagged this as go/request-forgery — an admin
(or anyone who compromises the admin account) could point a node
at internal infrastructure (cloud metadata, RFC1918 ranges, etc.)
and the panel would dutifully fetch it.

Add util/netsafe with a shared TOCTOU-safe DialContext that
resolves the host, rejects private/internal IPs unless the
per-request context whitelists them (per-node AllowPrivateAddress
flag, plumbed through context.Value), and dials the resolved IP
directly so the IP that passed the check is the IP we connect to.
This closes the DNS-rebinding window where a hostname could
resolve to a public IP at check time and a private one at dial.

Also tighten address validation (NormalizeHost rejects anything
that isn't a bare hostname or IP literal — no embedded paths,
userinfo, schemes) and switch URL construction from fmt.Sprintf to
url.URL{} + net.JoinHostPort so admin-supplied values can't smuggle
URL components.

custom_geo.go's isBlockedIP now delegates to netsafe so there's
one source of truth.

web/runtime/remote.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -16,6 +17,7 @@ import (
 
 	"github.com/mhsanaei/3x-ui/v3/database/model"
 	"github.com/mhsanaei/3x-ui/v3/logger"
+	"github.com/mhsanaei/3x-ui/v3/util/netsafe"
 )
 
 const remoteHTTPTimeout = 10 * time.Second
@@ -25,6 +27,7 @@ var remoteHTTPClient = &http.Client{
 		MaxIdleConns:        64,
 		MaxIdleConnsPerHost: 4,
 		IdleConnTimeout:     60 * time.Second,
+		DialContext:         netsafe.SSRFGuardedDialContext,
 	},
 }
 
@@ -50,7 +53,18 @@ func NewRemote(n *model.Node) *Remote {
 
 func (r *Remote) Name() string { return "node:" + r.node.Name }
 
-func (r *Remote) baseURL() string {
+func (r *Remote) baseURL() (string, error) {
+	addr, err := netsafe.NormalizeHost(r.node.Address)
+	if err != nil {
+		return "", err
+	}
+	scheme := r.node.Scheme
+	if scheme != "http" && scheme != "https" {
+		scheme = "https"
+	}
+	if r.node.Port <= 0 || r.node.Port > 65535 {
+		return "", fmt.Errorf("invalid node port %d", r.node.Port)
+	}
 	bp := r.node.BasePath
 	if bp == "" {
 		bp = "/"
@@ -58,7 +72,12 @@ func (r *Remote) baseURL() string {
 	if !strings.HasSuffix(bp, "/") {
 		bp += "/"
 	}
-	return fmt.Sprintf("%s://%s:%d%s", r.node.Scheme, r.node.Address, r.node.Port, bp)
+	u := &url.URL{
+		Scheme: scheme,
+		Host:   net.JoinHostPort(addr, strconv.Itoa(r.node.Port)),
+		Path:   bp,
+	}
+	return u.String(), nil
 }
 
 func (r *Remote) do(ctx context.Context, method, path string, body any) (*envelope, error) {
@@ -66,7 +85,11 @@ func (r *Remote) do(ctx context.Context, method, path string, body any) (*envelo
 		return nil, errors.New("node has no API token configured")
 	}
 
-	target := r.baseURL() + strings.TrimPrefix(path, "/")
+	base, err := r.baseURL()
+	if err != nil {
+		return nil, err
+	}
+	target := base + strings.TrimPrefix(path, "/")
 
 	var (
 		reqBody     io.Reader
@@ -78,15 +101,15 @@ func (r *Remote) do(ctx context.Context, method, path string, body any) (*envelo
 		reqBody = strings.NewReader(b.Encode())
 		contentType = "application/x-www-form-urlencoded"
 	default:
-		buf, err := json.Marshal(b)
-		if err != nil {
-			return nil, fmt.Errorf("marshal body: %w", err)
+		buf, jerr := json.Marshal(b)
+		if jerr != nil {
+			return nil, fmt.Errorf("marshal body: %w", jerr)
 		}
 		reqBody = bytes.NewReader(buf)
 		contentType = "application/json"
 	}
 
-	cctx, cancel := context.WithTimeout(ctx, remoteHTTPTimeout)
+	cctx, cancel := context.WithTimeout(netsafe.ContextWithAllowPrivate(ctx, r.node.AllowPrivateAddress), remoteHTTPTimeout)
 	defer cancel()
 	req, err := http.NewRequestWithContext(cctx, method, target, reqBody)
 	if err != nil {