Distribute master OTA images to slaves over ESP-NOW.

After UART OTA the master reads the staged partition in 4 KiB blocks (200 B ESP-NOW chunks), waits for per-slave block ACKs, and fixes the final partial block. Slaves reuse ota_uart; send pacing and logging improve reliability.

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

main/ota_espnow.h

@@ -0,0 +1,23 @@
+#ifndef OTA_ESPNOW_H
+#define OTA_ESPNOW_H
+
+#include "esp_err.h"
+#include "esp_now_messages.pb.h"
+#include "esp_partition.h"
+#include <stdint.h>
+
+/** Master: read staged image from partition and push to all available slaves. */
+esp_err_t ota_espnow_distribute(const esp_partition_t *partition, uint32_t size);
+
+/** Master: handle slave → master OTA status / block ACK. */
+void ota_espnow_master_on_status(const uint8_t slave_mac[6],
+                                 const alox_EspNowOtaStatus *status);
+
+/** Slave: handle master → slave OTA commands. */
+void ota_espnow_slave_on_start(const uint8_t master_mac[6],
+                               const alox_EspNowOtaStart *start);
+void ota_espnow_slave_on_payload(const uint8_t master_mac[6],
+                                 const alox_EspNowOtaPayload *payload);
+void ota_espnow_slave_on_end(const uint8_t master_mac[6]);
+
+#endif