Dim LED ring, add blink mode, and signal OTA outcome on the ring.

Default brightness is ~5%; UART blink mode and green/red pulses mark OTA success or failure. Failed UART uploads skip ESP-NOW distribution.

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

main/ota_uart.c

@@ -151,6 +151,10 @@ ota_feed_result_t ota_uart_feed(const uint8_t *data, size_t len) {
 
 uint32_t ota_uart_bytes_written(void) { return s_ota.written; }
 
+uint32_t ota_uart_bytes_received(void) { return s_ota.received; }
+
+uint32_t ota_uart_total_size(void) { return s_ota.active ? s_ota.total_size : 0; }
+
 bool ota_uart_get_staged_image(const esp_partition_t **partition_out,
                                uint32_t *size_out) {
   if (!s_staged.valid || s_staged.partition == NULL) {