Add per-slave ESP-NOW OTA progress over UART and fix dashboard updates.

Expose OTA_SLAVE_PROGRESS on the master, track per-slave state during
distribution, run ESP-NOW OTA in a background task so the host can poll
while slaves update, and show master/slave progress in the dashboard
with table layout and faster WebSocket refresh during uploads.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/dashboard.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log"
 	"sync"
@@ -105,14 +106,17 @@ func (h *wsHub) broadcastRaw(v any) {
 	}
 }
 
-func pollDashboard(link *managedSerial, portName string) DashboardState {
+func pollDashboard(link *managedSerial, portName string, last *DashboardState) DashboardState {
 	st := DashboardState{
 		UpdatedAt:  time.Now().Format(time.RFC3339),
 		SerialPort: portName,
 		Clients:    []ClientView{},
 	}
 
-	ver, err := link.getVersion()
+	ver, err := link.getVersionPoll()
+	if errors.Is(err, errUARTBusy) {
+		return pausedPollState(portName, last)
+	}
 	if err != nil {
 		return disconnectedState(portName, err)
 	}
@@ -124,12 +128,15 @@ func pollDashboard(link *managedSerial, portName string) DashboardState {
 		RunningPartition: ver.GetRunningPartition(),
 		OK:               true,
 	}
-	if dz, err := readDeadzone(link, 0); err == nil {
+	if dz, err := readDeadzonePoll(link, 0); err == nil {
 		st.Master.Deadzone = dz
 	}
 
-	clients, err := link.listClients()
+	clients, err := link.listClientsPoll()
 	if err != nil {
+		if errors.Is(err, errUARTBusy) {
+			return pausedPollState(portName, last)
+		}
 		st.SerialOK = false
 		st.SerialError = err.Error()
 		st.UARTConnected = link.IsConnected()
@@ -146,7 +153,7 @@ func pollDashboard(link *managedSerial, portName string) DashboardState {
 			LastPing:        c.GetLastPing(),
 			LastSuccessPing: c.GetLastSuccessPing(),
 		}
-		if dz, err := readDeadzone(link, c.GetId()); err == nil {
+		if dz, err := readDeadzonePoll(link, c.GetId()); err == nil {
 			cv.Deadzone = dz
 		}
 		st.Clients = append(st.Clients, cv)
@@ -154,6 +161,18 @@ func pollDashboard(link *managedSerial, portName string) DashboardState {
 	return st
 }
 
+func pausedPollState(portName string, last *DashboardState) DashboardState {
+	if last != nil && last.UARTConnected {
+		st := *last
+		st.UpdatedAt = time.Now().Format(time.RFC3339)
+		st.SerialPort = portName
+		st.SerialOK = true
+		st.SerialError = "Live-Polling pausiert (OTA läuft)"
+		return st
+	}
+	return disconnectedState(portName, errUARTBusy)
+}
+
 func readDeadzone(link *managedSerial, clientID uint32) (uint32, error) {
 	r, err := link.AccelDeadzone(&pb.AccelDeadzoneRequest{
 		Write:    false,
@@ -168,6 +187,20 @@ func readDeadzone(link *managedSerial, clientID uint32) (uint32, error) {
 	return r.GetDeadzone(), nil
 }
 
+func readDeadzonePoll(link *managedSerial, clientID uint32) (uint32, error) {
+	r, err := link.AccelDeadzonePoll(&pb.AccelDeadzoneRequest{
+		Write:    false,
+		ClientId: clientID,
+	})
+	if err != nil {
+		return 0, err
+	}
+	if !r.GetSuccess() {
+		return 0, fmt.Errorf("deadzone read failed for client %d", clientID)
+	}
+	return r.GetDeadzone(), nil
+}
+
 func formatMAC(mac []byte) string {
 	if len(mac) == 0 {
 		return ""
@@ -180,8 +213,12 @@ func runPoller(link *managedSerial, portName string, hub *wsHub, interval time.D
 	defer ticker.Stop()
 
 	uartUp := false
+	var lastGood DashboardState
 	publish := func() {
-		st := pollDashboard(link, portName)
+		st := pollDashboard(link, portName, &lastGood)
+		if st.UARTConnected && st.SerialOK {
+			lastGood = st
+		}
 		if st.UARTConnected && !uartUp {
 			log.Printf("UART %s connected", portName)
 		}