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>

main/ota_espnow.h

@@ -4,10 +4,20 @@
 #include "esp_err.h"
 #include "esp_now_messages.pb.h"
 #include "esp_partition.h"
+#include "uart_messages.pb.h"
 #include <stdint.h>
 
+typedef struct {
+  /** bytes_done, total_bytes, number of slaves targeted. */
+  void (*aggregate)(uint32_t bytes_done, uint32_t total_bytes,
+                    uint8_t slave_count);
+  /** Per-slave block ACK (slave_id, bytes_written on that slave, total_bytes). */
+  void (*per_slave)(uint32_t slave_id, uint32_t bytes_done, uint32_t total_bytes);
+} ota_espnow_progress_cbs_t;
+
 /** 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);
+esp_err_t ota_espnow_distribute(const esp_partition_t *partition, uint32_t size,
+                                const ota_espnow_progress_cbs_t *progress);
 
 /** Master: handle slave → master OTA status / block ACK. */
 void ota_espnow_master_on_status(const uint8_t slave_mac[6],
@@ -20,4 +30,11 @@ 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]);
 
+/**
+ * Fill UART OtaSlaveProgressResponse from tracked per-slave state.
+ * filter_client_id 0 = all slaves in the last/current distribution session.
+ */
+void ota_espnow_progress_query(uint32_t filter_client_id,
+                               alox_OtaSlaveProgressResponse *out);
+
 #endif