feat: add settings components and persistence tests

CMakeLists.txt

@@ -1,4 +1,7 @@
 cmake_minimum_required(VERSION 3.10)
 project(MC_APP_BOILERPLATE VERSION 0.1.0 LANGUAGES C CXX)
 
+set(PROJECT_EXTRA_COMPONENT_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/components" CACHE PATH
+    "Common ESP-IDF components" FORCE)
+
 include(platforms/desktop/CMakeLists.txt)

components/CMakeLists.txt

@@ -0,0 +1,10 @@
+set(PROJECT_COMPONENTS
+    settings_core
+    settings_ui
+    connection_tester
+    net_sntp
+    ota_update
+    diag
+    backup_server
+    CACHE INTERNAL "Registered user components"
+)

components/backup_server/CMakeLists.txt

@@ -0,0 +1,11 @@
+idf_component_register(
+    SRCS
+        "src/backup_server.c"
+        "src/backup_format.c"
+    INCLUDE_DIRS
+        "include"
+    REQUIRES
+        settings_core
+        esp_http_server
+        log
+)

components/backup_server/include/backup_server/backup_format.h

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#pragma once
+
+#include <stddef.h>
+
+#include "esp_err.h"
+#include "settings_core/app_cfg.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    size_t    backup_server_calculate_json_size(const app_cfg_t* cfg);
+    esp_err_t backup_server_write_json(const app_cfg_t* cfg, char* buffer, size_t length);
+
+#ifdef __cplusplus
+}
+#endif

components/backup_server/include/backup_server/backup_server.h

@@ -0,0 +1,28 @@
+/*
+ * SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#pragma once
+
+#include "esp_err.h"
+#include "esp_http_server.h"
+#include "settings_core/app_cfg.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    typedef struct
+    {
+        httpd_handle_t   httpd;
+        const app_cfg_t* cfg;
+    } backup_server_handle_t;
+
+    esp_err_t backup_server_start(backup_server_handle_t* handle, const app_cfg_t* cfg);
+    void      backup_server_stop(backup_server_handle_t* handle);
+
+#ifdef __cplusplus
+}
+#endif