esp32 improvements

- better clock seconds
- better alarm (image before audio, supposedly)

components/audio_client/audio_client.cpp

@@ -35,6 +35,7 @@ static uint8_t s_img_buf[STATUS_IMG_BYTES];
 static lv_img_dsc_t s_img_dsc;
 static volatile bool s_img_pending = false;   /* expecting binary frame with image data */
 static volatile bool s_img_updated = false;   /* new image ready for UI consumption */
+static TaskHandle_t s_img_notify_task = NULL;  /* task to wake on new image */
 
 /* Forward declarations */
 static void playback_task(void *arg);
@@ -121,6 +122,9 @@ static void handle_binary_frame(const uint8_t *data, int len)
         if (len == STATUS_IMG_BYTES) {
             memcpy(s_img_buf, data, STATUS_IMG_BYTES);
             s_img_updated = true;
+            if (s_img_notify_task) {
+                xTaskNotifyGive(s_img_notify_task);
+            }
             ESP_LOGI(TAG, "Status image received (%d bytes)", len);
         } else {
             ESP_LOGW(TAG, "Status image size mismatch: got %d, expected %d", len, STATUS_IMG_BYTES);
@@ -262,6 +266,11 @@ audio_state_t audio_client_get_state(void)
     return s_state;
 }
 
+void audio_client_set_image_notify_task(TaskHandle_t task)
+{
+    s_img_notify_task = task;
+}
+
 const lv_img_dsc_t *audio_client_get_status_image(bool *updated)
 {
     if (updated) {

components/audio_client/audio_client.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include <stdbool.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
 #include "lvgl.h"
 
 #ifdef __cplusplus
@@ -30,6 +32,12 @@ void audio_client_stop(void);
 /** Get current audio client state. */
 audio_state_t audio_client_get_state(void);
 
+/**
+ * Register a task to be notified (via xTaskNotifyGive) when a new status
+ * image arrives.  Call before audio_client_start().
+ */
+void audio_client_set_image_notify_task(TaskHandle_t task);
+
 /**
  * Get the latest status image descriptor.
  * @param updated  Set to true if a new image arrived since last call, then reset.