Refactor NVS and WiFi handlers for improved memory management and logging

- Updated KVStorageHandler interface to use std::string instead of char* for key-value operations.
- Enhanced NVSStorageHandler to utilize ESP_LOG for error and info messages instead of printf.
- Refactored WifiHandler to manage WiFi credentials using JSON format for better structure and storage.
- Replaced raw pointers with std::unique_ptr in WifiHandler and NetworkHandler for automatic memory management.
- Removed unused TouchHandler and EInkTouchHandler classes to clean up the codebase.
- Adjusted CMakeLists.txt to remove unnecessary include directories.
- Updated lv_conf.h to enable FreeRTOS and gesture recognition features.

main/network/wifi_handler.h

@@ -3,7 +3,9 @@
 #include "esp_wifi.h"
 #include "freertos/event_groups.h"
 
-#define WIFI_CONNECTED_BIT (1 << 0)
+#define WIFI_STARTED_BIT   (1 << 0)
+#define WIFI_CONNECTED_BIT (1 << 1)
+
 
 class WifiHandler {
 public:
@@ -11,16 +13,13 @@ 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
-    KVStorageHandler* kvs
+    std::unique_ptr<KVStorageHandler> kvs
   );
   ~WifiHandler();
 
-  // move semantics
-  WifiHandler(WifiHandler&& other) noexcept;
-
-  void init();
-  esp_err_t connect(const char* ssid, const char* password);
-  esp_err_t connect(const char* ssid); // connect using stored password
+  esp_err_t init();
+  esp_err_t connect(const std::string& ssid, const std::string& password);
+  esp_err_t connect(const std::string& ssid); // connect using stored password
   esp_err_t reconnect(); // reconnect to current SSID
   void disconnect();
   EventBits_t wait_for_connection(TickType_t ticks_to_wait);
@@ -37,17 +36,21 @@ private:
   // prevent copying
   WifiHandler(const WifiHandler&) = delete;
   WifiHandler& operator=(const WifiHandler&) = delete;
+  // prevent moving
+  WifiHandler(WifiHandler&& other) = delete;
+  WifiHandler& operator=(WifiHandler&& other) = delete;
 
-  char* build_password_key(const char* ssid);
-  void get_wifi_credentials(char*& ssid, char*& password);
+  void store_wifi_credentials(const std::string& ssid, const std::string& password);
+  void get_wifi_credentials(std::string& out_ssid, std::string& out_password);
 
   bool initialized = false;
-  KVStorageHandler* kvs = nullptr;
+  std::unique_ptr<KVStorageHandler> kvs = nullptr;
   EventGroupHandle_t s_wifi_event_group = 0;
   SemaphoreHandle_t scan_mutex = nullptr;
   SemaphoreHandle_t connection_mutex = nullptr;
+  SemaphoreHandle_t credential_mutex = nullptr;
   // current connected / preferred SSID
-  char* current_ssid = nullptr;
+  std::string current_ssid;
   // prevent auto-reconnect on expected disconnection, e.g. when user calls disconnect()
   // should be reset to false after connect()
   bool expect_disconnected = false;