Add web dashboard OTA upload with live progress.

Share UART OTA logic between CLI and serve via POST /api/ota, WebSocket progress events, and a dashboard upload UI showing the running partition.

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

goTool/dashboard.go

@@ -14,11 +14,12 @@ import (
 )
 
 type MasterView struct {
-	Version  uint32 `json:"version"`
-	GitHash  string `json:"git_hash"`
-	Deadzone uint32 `json:"deadzone,omitempty"`
-	OK       bool   `json:"ok"`
-	Error    string `json:"error,omitempty"`
+	Version           uint32 `json:"version"`
+	GitHash           string `json:"git_hash"`
+	RunningPartition  string `json:"running_partition,omitempty"`
+	Deadzone          uint32 `json:"deadzone,omitempty"`
+	OK                bool   `json:"ok"`
+	Error             string `json:"error,omitempty"`
 }
 
 type ClientView struct {
@@ -87,6 +88,23 @@ func (h *wsHub) unregister(c *websocket.Conn) {
 	h.mu.Unlock()
 }
 
+func (h *wsHub) broadcastRaw(v any) {
+	h.mu.RLock()
+	conns := make([]*websocket.Conn, 0, len(h.clients))
+	for c := range h.clients {
+		conns = append(conns, c)
+	}
+	h.mu.RUnlock()
+
+	data, err := json.Marshal(v)
+	if err != nil {
+		return
+	}
+	for _, c := range conns {
+		_ = c.WriteMessage(websocket.TextMessage, data)
+	}
+}
+
 func pollDashboard(link *managedSerial, portName string) DashboardState {
 	st := DashboardState{
 		UpdatedAt:  time.Now().Format(time.RFC3339),
@@ -101,9 +119,10 @@ func pollDashboard(link *managedSerial, portName string) DashboardState {
 	st.UARTConnected = true
 	st.SerialOK = true
 	st.Master = MasterView{
-		Version: ver.GetVersion(),
-		GitHash: ver.GetGitHash(),
-		OK:      true,
+		Version:          ver.GetVersion(),
+		GitHash:          ver.GetGitHash(),
+		RunningPartition: ver.GetRunningPartition(),
+		OK:               true,
 	}
 	if dz, err := readDeadzone(link, 0); err == nil {
 		st.Master.Deadzone = dz