feat(dashboard): more System History metrics, persistence & localized labels

- Sample swap %, TCP/UDP connection counts and disk-usage % on the host ticker
- System History: Swap overlaid on the RAM tab, plus new Connections and Disk Usage tabs
- Persist the host time-series across restarts: gob snapshot beside the DB, written on a timer and at shutdown, restored on boot
- Live-refresh the open chart (2s for short ranges, 10s for longer)
- Localize CPU/RAM/Swap and the new tab/chart titles across all 13 languages and route legend series names through i18n

web/service/metric_history.go

@@ -1,8 +1,14 @@
 package service
 
 import (
+	"encoding/gob"
+	"os"
+	"path/filepath"
 	"sync"
 	"time"
+
+	"github.com/mhsanaei/3x-ui/v3/config"
+	"github.com/mhsanaei/3x-ui/v3/logger"
 )
 
 // MetricSample is one point of any time-series we keep in memory.
@@ -59,6 +65,34 @@ func (h *metricHistory) drop(metric string) {
 	h.mu.Unlock()
 }
 
+// snapshot returns a deep copy of every series, safe to serialize without
+// holding the lock during disk I/O.
+func (h *metricHistory) snapshot() map[string][]MetricSample {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	out := make(map[string][]MetricSample, len(h.metrics))
+	for k, v := range h.metrics {
+		cp := make([]MetricSample, len(v))
+		copy(cp, v)
+		out[k] = cp
+	}
+	return out
+}
+
+// restore replaces the in-memory series with a previously persisted set,
+// re-applying the per-series capacity cap so a tampered or oversized file
+// can't grow the working set unbounded.
+func (h *metricHistory) restore(data map[string][]MetricSample) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	for k, v := range data {
+		if len(v) > metricCapacityDefault {
+			v = v[len(v)-metricCapacityDefault:]
+		}
+		h.metrics[k] = v
+	}
+}
+
 // aggregate returns up to maxPoints buckets of size bucketSeconds,
 // each bucket carrying the arithmetic mean of the underlying samples.
 // Bucket alignment is to absolute Unix-second boundaries so two
@@ -137,7 +171,7 @@ var (
 // status sample. Exposed for documentation/test purposes; the
 // controller validates incoming names against an allow-list.
 var SystemMetricKeys = []string{
-	"cpu", "mem", "netUp", "netDown", "pktUp", "pktDown", "diskRead", "diskWrite", "online", "load1", "load5", "load15",
+	"cpu", "mem", "swap", "netUp", "netDown", "pktUp", "pktDown", "diskRead", "diskWrite", "diskUsage", "tcpCount", "udpCount", "online", "load1", "load5", "load15",
 }
 
 // NodeMetricKeys lists the per-node metric names NodeHeartbeatJob writes.
@@ -150,3 +184,54 @@ var NodeMetricKeys = []string{"cpu", "mem"}
 var XrayMetricKeys = []string{
 	"xrAlloc", "xrSys", "xrHeapObjects", "xrNumGC", "xrPauseNs",
 }
+
+// systemMetricsStorePath is where the host time-series is persisted between
+// restarts. It lives next to the database so a single volume mount carries
+// both. Only systemMetrics is persisted — node and xray series are cheap to
+// rebuild and tied to live connections.
+func systemMetricsStorePath() string {
+	return filepath.Join(config.GetDBFolderPath(), "system_metrics.gob")
+}
+
+// PersistSystemMetrics writes the host time-series to disk via a temp file +
+// rename so a crash mid-write can't corrupt the previous snapshot. Called on a
+// timer and at shutdown.
+func PersistSystemMetrics() error {
+	path := systemMetricsStorePath()
+	tmp := path + ".tmp"
+	f, err := os.Create(tmp)
+	if err != nil {
+		return err
+	}
+	if err := gob.NewEncoder(f).Encode(systemMetrics.snapshot()); err != nil {
+		f.Close()
+		os.Remove(tmp)
+		return err
+	}
+	if err := f.Close(); err != nil {
+		os.Remove(tmp)
+		return err
+	}
+	return os.Rename(tmp, path)
+}
+
+// RestoreSystemMetrics loads a previously persisted host time-series on startup.
+// A missing file is not an error (first boot). Aggregation already windows by
+// time, so any gap from downtime is handled by the readers.
+func RestoreSystemMetrics() {
+	path := systemMetricsStorePath()
+	f, err := os.Open(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			logger.Warning("restore system metrics failed:", err)
+		}
+		return
+	}
+	defer f.Close()
+	var data map[string][]MetricSample
+	if err := gob.NewDecoder(f).Decode(&data); err != nil {
+		logger.Warning("decode system metrics failed:", err)
+		return
+	}
+	systemMetrics.restore(data)
+}

web/service/server.go

@@ -565,12 +565,22 @@ func (s *ServerService) AppendStatusSample(t time.Time, status *Status) {
 	if status.Mem.Total > 0 {
 		systemMetrics.append("mem", t, float64(status.Mem.Current)*100.0/float64(status.Mem.Total))
 	}
+	if status.Swap.Total > 0 {
+		systemMetrics.append("swap", t, float64(status.Swap.Current)*100.0/float64(status.Swap.Total))
+	} else {
+		systemMetrics.append("swap", t, 0)
+	}
 	systemMetrics.append("netUp", t, float64(status.NetIO.Up))
 	systemMetrics.append("netDown", t, float64(status.NetIO.Down))
 	systemMetrics.append("diskRead", t, float64(status.DiskIO.Read))
 	systemMetrics.append("diskWrite", t, float64(status.DiskIO.Write))
+	if status.Disk.Total > 0 {
+		systemMetrics.append("diskUsage", t, float64(status.Disk.Current)*100.0/float64(status.Disk.Total))
+	}
 	systemMetrics.append("pktUp", t, float64(status.NetIO.PktUp))
 	systemMetrics.append("pktDown", t, float64(status.NetIO.PktDown))
+	systemMetrics.append("tcpCount", t, float64(status.TcpCount))
+	systemMetrics.append("udpCount", t, float64(status.UdpCount))
 	online := 0
 	if p != nil && p.IsRunning() {
 		online = len(p.GetOnlineClients())