Configurable update interval (100 ms – 2 s): drives daemon sampling and UI polling, saved with the dashboard layout

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/api/server.go

@@ -50,6 +50,11 @@ func New(cfg *config.Config, sessions *auth.Sessions, mgr *term.Manager, col *me
 	if s.user == "" {
 		s.user = "?"
 	}
+	// The saved dashboard layout carries the sampling interval; apply it on boot.
+	var raw json.RawMessage
+	st.View(func(x *store.State) { raw = x.Dashboard })
+	s.applyPrefs(raw)
+
 	m := http.NewServeMux()
 	m.HandleFunc("GET /healthz", func(w http.ResponseWriter, _ *http.Request) { w.WriteHeader(204) })
 	m.HandleFunc("POST /api/login", s.login)
@@ -212,9 +217,25 @@ func (s *Server) putDashPrefs(w http.ResponseWriter, r *http.Request) {
 		jsonErr(w, 500, err.Error())
 		return
 	}
+	s.applyPrefs(b)
 	w.WriteHeader(204)
 }
 
+// applyPrefs picks the few layout fields the server acts on (just the interval).
+func (s *Server) applyPrefs(raw []byte) {
+	var p struct {
+		IntervalMs int `json:"intervalMs"`
+	}
+	if len(raw) == 0 || json.Unmarshal(raw, &p) != nil {
+		return
+	}
+	if p.IntervalMs > 0 {
+		s.metrics.SetInterval(time.Duration(p.IntervalMs) * time.Millisecond)
+	} else {
+		s.metrics.SetInterval(metrics.DefaultInterval)
+	}
+}
+
 // ---- terminals ----
 
 func (s *Server) listTerminals(w http.ResponseWriter, _ *http.Request) {