Add run limit feature for relay channels with NVS support

- Introduced configuration options for enabling run limits in Kconfig.
- Added APIs to get and set run limits for individual relay channels.
- Implemented run limit timer functionality to automatically stop channels.
- Updated NVS handling to store and retrieve run limit values.
- Enhanced documentation in README and code comments to reflect new feature.

Closes #1080

private_include/relay_chn_core.h

@@ -33,6 +33,20 @@ ESP_EVENT_DECLARE_BASE(RELAY_CHN_CMD_EVENT);
  */
 esp_err_t relay_chn_init_timer(relay_chn_ctl_t *chn_ctl);
 
+#if RELAY_CHN_ENABLE_RUN_LIMIT == 1
+/**
+ * @brief Initializes the relay channel run limit timer.
+ * 
+ * This function creates a timer for the relay channel to handle run time limit.
+ * Required by *_ctl_* module.
+ * 
+ * @param chn_ctl Pointer to the relay channel control structure.
+ * 
+ * @return esp_err_t ESP_OK on success, or an error code on failure.
+ */
+esp_err_t relay_chn_init_run_limit_timer(relay_chn_ctl_t *chn_ctl);
+#endif // RELAY_CHN_ENABLE_RUN_LIMIT
+
 /**
  * @brief Issues a command to the relay channel.
  * 

private_include/relay_chn_nvs.h

@@ -45,6 +45,26 @@ esp_err_t relay_chn_nvs_set_direction(uint8_t ch, relay_chn_direction_t directio
  */
 esp_err_t relay_chn_nvs_get_direction(uint8_t ch, relay_chn_direction_t *direction);
 
+#if RELAY_CHN_ENABLE_RUN_LIMIT == 1
+/**
+ * @brief Store relay channel run limit in NVS.
+ *
+ * @param[in] ch Channel number.
+ * @param[in] direction Run limit value to store.
+ * @return ESP_OK on success, error code otherwise.
+ */
+esp_err_t relay_chn_nvs_set_run_limit(uint8_t ch, uint16_t time_sec);
+
+/**
+ * @brief Retrieve relay channel run limit from NVS.
+ *
+ * @param[in] ch Channel number.
+ * @param[out] direction Pointer to store retrieved run limit value.
+ * @return ESP_OK on success, error code otherwise.
+ */
+esp_err_t relay_chn_nvs_get_run_limit(uint8_t ch, uint16_t *time_sec);
+#endif // RELAY_CHN_ENABLE_RUN_LIMIT == 1
+
 #ifdef RELAY_CHN_ENABLE_TILTING
 /**
  * @brief Store tilt sensitivity in NVS.

private_include/relay_chn_priv_types.h

@@ -68,6 +68,10 @@ typedef struct {
     relay_chn_output_t *output;         /*!< Output configuration of the relay channel */
     relay_chn_cmd_t pending_cmd;        /*!< The command that is pending to be issued */
     esp_timer_handle_t inertia_timer;   /*!< Timer to handle the opposite direction inertia time */
+#if RELAY_CHN_ENABLE_RUN_LIMIT == 1
+    esp_timer_handle_t run_limit_timer; /*!< Timer to handle the run limit */
+    uint16_t run_limit_sec;             /*!< Run limit in seconds */
+#endif
 #if RELAY_CHN_ENABLE_TILTING == 1
     relay_chn_tilt_ctl_t *tilt_ctl;     /*!< Pointer to the tilt control structure if tilting is enabled */
 #endif