Implement ExpandString struct to handle Windows environment variable expansion
with proper error handling. Also reorganize windows-sys dependencies and improve
icon loading error messages.
Move winreg_extra functionality into new extra/winreg module and restructure project layout
Add Windows icon handling utilities in extra/windows module
Update dependencies and clean up unused wincmd module
- Implement query_ext method to check default program associations
- Enhance CLI query command with tabular output showing associations
- Refactor program building into Composition struct for better organization
- Update documentation comments for clarity
- Add WFHasPrivilege function to check user privileges
- Refactor ProgId structure to use standard format with optional version
- Improve registry operations with safer key/value handling
- Update dependencies to include Win32_System_Registry
- Add `link_ext` and `unlink_ext` methods to Program for managing file associations
- Introduce new error variants for invalid tokens
- Add utility function `capitalize_first_ascii` for ProgId generation
- Implement registry key operations for user and system scopes
- Add new modules for Windows command line handling (wincmd) and registry extensions (winreg_extra)
- Replace Manner struct with simple String and add identifier validation
- Update WFAdd function signature and add new WFStartup/WFShutdown functions
- Implement ExpandString wrapper for registry operations
