error handling and cleanup

main/sntp.h

@@ -1,11 +1,37 @@
+/**
+ * @file sntp.h
+ * @brief SNTP client for time synchronization.
+ *
+ * This module synchronizes system time with an NTP server.
+ * Time sync is required for schedule-based heating control.
+ */
+
 #pragma once
 
+#include "esp_err.h"
+
+/**
+ * @brief SNTP synchronization state enumeration.
+ */
 typedef enum _SntpState
 {
-    SYNC_SUCCESSFUL,
-    SYNC_NOT_STARTED,
-    SYNC_FAILED,
+    SYNC_SUCCESSFUL,  /**< Time synchronized successfully. */
+    SYNC_NOT_STARTED, /**< Synchronization not yet attempted. */
+    SYNC_FAILED,      /**< Synchronization failed. */
 } eSntpState;
 
-void initSntp(void);
-eSntpState getSntpState(void);
+/**
+ * @brief Initialize the SNTP client.
+ *
+ * Configures SNTP with the server from Kconfig and starts
+ * periodic time synchronization.
+ *
+ * @return ESP_OK on success, ESP_FAIL on error.
+ */
+esp_err_t initSntp(void);
+
+/**
+ * @brief Get the current SNTP synchronization state.
+ * @return eSntpState indicating sync status.
+ */
+eSntpState getSntpState(void);