Refactor ConfigManager to use const-correctness for parameters

Updated method signatures to use const references for default values, improving memory efficiency and clarifying immutability. Also marked `requiresRestart` as a `const` method to ensure it doesn't modify the object's state.

Author: flattermann

firmware/src/core/configmanager/ConfigManager.cpp

@@ -268,19 +268,19 @@ void ConfigManager::addConfigComboBox(const char *section, const char *varName,
     addConfigComboBox(section, varName, var, options, numOptions, i18n(description), advanced);
 }
 
-std::string ConfigManager::getConfigString(const char *varName, std::string defaultValue) {
+std::string ConfigManager::getConfigString(const char *varName, const std::string &defaultValue) {
     return m_preferences.getString(varName, defaultValue.c_str()).c_str();
 }
 
-bool ConfigManager::getConfigBool(const char *varName, bool defaultValue) {
+bool ConfigManager::getConfigBool(const char *varName, const bool defaultValue) {
     return m_preferences.getBool(varName, defaultValue);
 }
 
-int ConfigManager::getConfigInt(const char *varName, int defaultValue) {
+int ConfigManager::getConfigInt(const char *varName, const int defaultValue) {
     return m_preferences.getInt(varName, defaultValue);
 }
 
-float ConfigManager::getConfigFloat(const char *varName, float defaultValue) {
+float ConfigManager::getConfigFloat(const char *varName, const float defaultValue) {
     return m_preferences.getFloat(varName, defaultValue);
 }
 

firmware/src/core/configmanager/ConfigManager.h

@@ -70,7 +70,7 @@ class ConfigManager {
     }
 
     // Retrieve a string configuration value, with a default fallback
-    std::string getConfigString(const char *varName, std::string defaultValue);
+    std::string getConfigString(const char *varName, const std::string &defaultValue);
     // Retrieve a boolean configuration value, with a default fallback
     bool getConfigBool(const char *varName, bool defaultValue);
     // Retrieve an integer configuration value, with a default fallback
@@ -88,7 +88,7 @@ class ConfigManager {
         const std::function<void(const char *section, const char *varName)> &callback);
 
     // Check if a restart is required
-    bool requiresRestart() { return m_requiresRestart; }
+    bool requiresRestart() const { return m_requiresRestart; }
 
 private:
     struct Parameter {