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>
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>
