Raise host frame payload limit so multi-client UART replies fit.

Use a uint16 LE length and 1024-byte max payload so CLIENT_INFO and BATTERY_STATUS no longer fail encoding past ~10 connected pods.

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

main/uart_proto.c

@@ -1,18 +1,26 @@
 #include "uart_proto.h"
+#include "esp_log.h"
 #include "pb_encode.h"
 #include "uart.h"
 #include <string.h>
 
+static const char *TAG = "[UART_PROTO]";
+
 esp_err_t uart_send_uart_message(const alox_UartMessage *msg) {
   uint8_t pb_buf[MAX_PAYLOAD_SIZE];
   pb_ostream_t stream = pb_ostream_from_buffer(pb_buf, sizeof(pb_buf));
 
   if (!pb_encode(&stream, alox_UartMessage_fields, msg)) {
+    ESP_LOGE(TAG, "pb_encode failed type=%u (%s)", (unsigned)msg->type,
+             PB_GET_ERROR(&stream));
     return ESP_FAIL;
   }
 
   uint8_t payload[MAX_PAYLOAD_SIZE];
   if (stream.bytes_written + 1 > sizeof(payload)) {
+    ESP_LOGE(TAG, "payload too large type=%u need=%u max=%u",
+             (unsigned)msg->type, (unsigned)(stream.bytes_written + 1),
+             (unsigned)sizeof(payload));
     return ESP_ERR_NO_MEM;
   }