implement reset via back button

Signed-off-by: Peter Siegmund <developer@mars3142.org>

firmware/components/persistence-manager/include/persistence_manager.h

@@ -28,6 +28,15 @@ extern "C"
         bool initialized;
     } persistence_manager_t;
 
+    /**
+     * @brief Erases the entire NVS flash (factory reset).
+     *
+     * Warning: This will remove all stored data and namespaces!
+     *
+     * @return esp_err_t ESP_OK on success, otherwise error code.
+     */
+    esp_err_t persistence_manager_factory_reset(void);
+
     /**
      * @brief Initialize the persistence manager with a given NVS namespace.
      *