Add command queue dispatcher and VERSION UART handler.

Centralize command dispatch over a FreeRTOS queue so UART and future
ESP-NOW transports can register handlers; implement the protobuf VERSION
command with framed nanopb responses including build git hash.

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

main/uart.c

@@ -1,3 +1,4 @@
+#include "cmd_handler.h"
 #include "driver/uart.h"
 #include "driver/gpio.h"
 #include "esp_log.h"
@@ -8,11 +9,40 @@
 #include "portmacro.h"
 #include "uart.h"
 #include <stdbool.h>
+#include <stdlib.h>
 #include <string.h>
 
 static const char *TAG = "[UART]";
 static QueueHandle_t uart_cmd_queue;
 
+static bool uart_enqueue_packet(const uart_packet_t *packet) {
+  if (packet->len == 0) {
+    return false;
+  }
+
+  generic_msg_t msg = {
+      .msg_id = packet->payload[0],
+      .len = packet->len > 1 ? packet->len - 1 : 0,
+      .payload = NULL,
+  };
+
+  if (msg.len > 0) {
+    msg.payload = malloc(msg.len);
+    if (msg.payload == NULL) {
+      ESP_LOGE(TAG, "failed to allocate command payload");
+      return false;
+    }
+    memcpy(msg.payload, &packet->payload[1], msg.len);
+  }
+
+  if (xQueueSend(uart_cmd_queue, &msg, 0) != pdPASS) {
+    free(msg.payload);
+    ESP_LOGW(TAG, "command queue full");
+    return false;
+  }
+  return true;
+}
+
 void init_uart(QueueHandle_t cmd_queue) {
   uart_cmd_queue = cmd_queue;
   uart_config_t uart_config = {// .baud_rate = 115200, // 921600, 115200
@@ -44,8 +74,9 @@ void uart_read_task(void *param) {
     if (len > 0) {
       for (int i = 0; i < len; ++i) {
         if (parse_uart_byte(data[i], &packet)) {
-          ESP_LOGI("UART", "Paket empfangen! Länge: %d", packet.len);
-          xQueueSend(uart_cmd_queue, &packet, 0);
+          ESP_LOGI(TAG, "packet received, len=%d, cmd=0x%02x", packet.len,
+                   packet.len > 0 ? packet.payload[0] : 0);
+          uart_enqueue_packet(&packet);
         }
       }
       last_byte_time = xTaskGetTickCount();
@@ -107,3 +138,30 @@ bool parse_uart_byte(uint8_t byte, uart_packet_t *p) {
   }
   return false;
 }
+
+esp_err_t uart_send_framed(const uint8_t *payload, size_t len) {
+  if (payload == NULL || len == 0 || len > MAX_PAYLOAD_SIZE) {
+    return ESP_ERR_INVALID_ARG;
+  }
+
+  uint8_t checksum = 0;
+  for (size_t i = 0; i < len; i++) {
+    checksum ^= payload[i];
+  }
+
+  uint8_t frame[4 + MAX_PAYLOAD_SIZE];
+  size_t pos = 0;
+  frame[pos++] = START_MARKER;
+  frame[pos++] = (uint8_t)len;
+  memcpy(&frame[pos], payload, len);
+  pos += len;
+  frame[pos++] = checksum;
+  frame[pos++] = STOP_MARKER;
+
+  int written =
+      uart_write_bytes(UART_NUM, frame, pos);
+  if (written < 0 || (size_t)written != pos) {
+    return ESP_FAIL;
+  }
+  return ESP_OK;
+}