feat: implement LittleFSHandler and FSGuard for improved file management

main/network/wifi_handler.h

@@ -1,5 +1,6 @@
 #pragma once
-#include "io/io.h"
+#include "freertos/FreeRTOS.h"
+#include "io/fs_handler.h"
 #include "esp_wifi.h"
 #include "freertos/event_groups.h"
 
@@ -13,7 +14,7 @@ public:
     // this handler is used to store/retrieve WiFi credentials
     // should have a unique namespace for WiFi credentials
     // it will be owned by WifiHandler and deleted in its destructor
-    std::unique_ptr<KVStorageHandler> kvs
+    std::shared_ptr<LittleFSHandler> fs_handler_
   );
   ~WifiHandler();
 
@@ -44,7 +45,7 @@ private:
   void get_wifi_credentials(std::string& out_ssid, std::string& out_password);
 
   bool initialized = false;
-  std::unique_ptr<KVStorageHandler> kvs = nullptr;
+  std::shared_ptr<LittleFSHandler> fs_handler_ = nullptr;
   EventGroupHandle_t s_wifi_event_group = 0;
   SemaphoreHandle_t scan_mutex = nullptr;
   SemaphoreHandle_t connection_mutex = nullptr;