feat(ntp): Live peer status tab (chronyc sources)

Adds GET /ntp/sources endpoint (runs chronyc sources, parses tabular
output) and a new "Peer status" tab in the NTP page showing all
configured peers with mode, state badge, stratum, poll interval,
reach register, last-rx and offset/error sample.

v1.1.101

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/handlers/ntp.go

@@ -41,6 +41,7 @@ func (h *NTPHandler) Register(rg *gin.RouterGroup) {
 	g.GET("/settings", h.GetSettings)
 	g.PUT("/settings", h.UpdateSettings)
 	g.GET("/status", h.Status)
+	g.GET("/sources", h.Sources)
 	g.POST("/force-sync", h.ForceSync)
 
 	p := g.Group("/pools")
@@ -250,6 +251,74 @@ func (h *NTPHandler) ForceSync(c *gin.Context) {
 	response.OK(c, gin.H{"message": "clock stepped", "output": string(out)})
 }
 
+// Sources liefert die aktuellen NTP-Quellen via `chronyc sources`.
+// Jede Zeile wird in ein NTPSource-Objekt geparst und als Array zurückgegeben.
+func (h *NTPHandler) Sources(c *gin.Context) {
+	out, err := exec.Command("chronyc", "sources").Output()
+	if err != nil {
+		response.OK(c, gin.H{
+			"sources": []any{},
+			"error":   "chronyc nicht verfügbar: " + err.Error(),
+		})
+		return
+	}
+	response.OK(c, gin.H{"sources": parseChronymSources(string(out))})
+}
+
+type ntpSource struct {
+	Mode    string `json:"mode"`
+	State   string `json:"state"`
+	Active  bool   `json:"active"`
+	Name    string `json:"name"`
+	Stratum int    `json:"stratum"`
+	Poll    int    `json:"poll"`
+	Reach   string `json:"reach"`
+	LastRx  string `json:"last_rx"`
+	Sample  string `json:"sample"`
+}
+
+func parseChronymSources(out string) []ntpSource {
+	modeMap := map[byte]string{'^': "server", '=': "peer", '#': "local"}
+	stateMap := map[byte]string{
+		'*': "synced", '+': "combined", '-': "not_combined",
+		'?': "unreachable", 'x': "error", '~': "variable",
+	}
+	var srcs []ntpSource
+	for _, line := range strings.Split(out, "\n") {
+		if len(line) < 2 {
+			continue
+		}
+		mode, ok := modeMap[line[0]]
+		if !ok {
+			continue
+		}
+		stateChar := line[1]
+		stateStr, ok := stateMap[stateChar]
+		if !ok {
+			stateStr = string(stateChar)
+		}
+		fields := strings.Fields(strings.TrimSpace(line[2:]))
+		if len(fields) < 5 {
+			continue
+		}
+		src := ntpSource{
+			Mode:   mode,
+			State:  stateStr,
+			Active: stateChar == '*' || stateChar == '+',
+			Name:   fields[0],
+			Reach:  fields[3],
+			LastRx: fields[4],
+		}
+		fmt.Sscanf(fields[1], "%d", &src.Stratum)
+		fmt.Sscanf(fields[2], "%d", &src.Poll)
+		if len(fields) >= 6 {
+			src.Sample = strings.Join(fields[5:], " ")
+		}
+		srcs = append(srcs, src)
+	}
+	return srcs
+}
+
 func validateNTPPool(p *models.NTPPool) error {
 	if p.Address == "" {
 		return errors.New("address required")