* perf: utilize smartstring for string handling
- Updated various modules to replace standard String with smartstring::alias::String for improved performance and memory efficiency.
- Adjusted string manipulations and conversions throughout the codebase to ensure compatibility with the new smartstring type.
- Enhanced readability and maintainability by using `.into()` for conversions where applicable.
- Ensured that all instances of string handling in configuration, logging, and network management leverage the benefits of smartstring.
* fix: replace wrap_err with stringify_err for better error handling in UWP tool invocation
* refactor: update import path for StringifyErr and adjust string handling in sysopt
* fix: correct import path for CmdResult in UWP module
* fix: update argument type for execute_sysproxy_command to use std::string::String
* fix: add missing CmdResult import in UWP platform module
* fix: improve string handling and error messaging across multiple files
* style: format code for improved readability and consistency across multiple files
* fix: remove unused file
* feat: local backup
* refactor(backup): make local backup helpers synchronous and clean up redundant checks
- Converted local backup helpers to synchronous functions to remove unused async warnings and align command signatures.
- Updated list/delete/export commands to call the sync feature functions directly without awaits while preserving behavior.
- Simplified destination directory creation to always ensure parent folders exist without redundant checks, satisfying Clippy.
