- Created libwsssht/ directory with modular components:
  * utils.h/c: Utility functions (print_usage, parse_connection_string, parse_args)
  * modes.h/c: Mode-specific functions (bridge, script, daemon modes)
  * threads.h/c: Thread-related functions and structures
  * wsssht.h: Main header with includes and declarations

- Reduced wsssht.c from 2769 lines to 674 lines (main function only)
- Updated Makefile and configure.sh to handle new modular structure
- Maintained exact same functionality and command-line interface
- Improved code maintainability and organization

All functionality preserved, build successful, and wsssht binary works correctly.