* feat: Implement language caching and improve language handling in i18n module
* refactor: Optimize i18n initialization with sync.Once for thread safety
* fix: Replace logging with fmt.Println for language file loading errors in i18n module
* fix: Correct format string in error logging for language file loading in i18n module
* fix: Update language files and improve error handling in i18n module
* fix: Update Malay language file extension from .yml to .yaml and add new translations in i18n module
* fix: Improve error messages for language file loading in i18n module
* fix: Ensure cached database language is set correctly during i18n initialization
* fix: Enhance language detection in i18n module by using Accept-Language header