fix(sub): source Userinfo total/expiry from client config in multi-node (#4645)

The Subscription-Userinfo header read total/expiry from client_traffics, but in a multi-node setup the master's node sync overwrites those with the node snapshot's zeros, so the header reported total=0; expire=0 even though the panel UI (which reads the clients table) showed the configured limits. AggregateTrafficByEmails now falls back to the clients table for total/expiry when the traffic row is zero, keeping up/down/lastOnline from client_traffics.

sub/subService_userinfo_test.go

@@ -0,0 +1,56 @@
+package sub
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/database"
+	"github.com/mhsanaei/3x-ui/v3/database/model"
+	"github.com/mhsanaei/3x-ui/v3/xray"
+)
+
+func TestAggregateTrafficByEmails_FallsBackToClientLimits(t *testing.T) {
+	dbDir := t.TempDir()
+	t.Setenv("XUI_DB_FOLDER", dbDir)
+	if err := database.InitDB(filepath.Join(dbDir, "x-ui.db")); err != nil {
+		t.Fatalf("InitDB: %v", err)
+	}
+	t.Cleanup(func() { _ = database.CloseDB() })
+
+	const email = "node-client@example.com"
+	const totalBytes = int64(300) * 1024 * 1024 * 1024
+	const expiry = int64(1893456000000)
+
+	db := database.GetDB()
+	if err := db.Create(&model.ClientRecord{
+		Email:      email,
+		TotalGB:    totalBytes,
+		ExpiryTime: expiry,
+		Enable:     true,
+	}).Error; err != nil {
+		t.Fatalf("seed client record: %v", err)
+	}
+	if err := db.Create(&xray.ClientTraffic{
+		Email:      email,
+		Up:         111,
+		Down:       222,
+		Total:      0,
+		ExpiryTime: 0,
+		Enable:     true,
+	}).Error; err != nil {
+		t.Fatalf("seed client traffic: %v", err)
+	}
+
+	var s SubService
+	agg, _ := s.AggregateTrafficByEmails([]string{email})
+
+	if agg.Up != 111 || agg.Down != 222 {
+		t.Errorf("usage = up %d/down %d, want 111/222", agg.Up, agg.Down)
+	}
+	if agg.Total != totalBytes {
+		t.Errorf("total = %d, want %d (fallback to clients table)", agg.Total, totalBytes)
+	}
+	if agg.ExpiryTime != expiry {
+		t.Errorf("expiry = %d, want %d (fallback to clients table)", agg.ExpiryTime, expiry)
+	}
+}