Add daemontools and s6 support

Features:

• Add compatibility layer for daemontools and s6 supervision systems
• New factory pattern for creating runit, daemontools, and s6 clients
• Support for multiple supervision system backends

Performance:

• Optimize status decode for zero allocations
• Improve memory efficiency in status operations

Improvements:

• Enhanced documentation with better examples and usage guides
• Expanded test coverage for all supervision systems
• Improved error handling in watch operations
• Better Makefile with more comprehensive build targets

Testing:

• Add integration tests for daemontools compatibility
• Add integration tests for s6 compatibility
• Expand factory validation test suite

This release maintains full backward compatibility while adding support
for daemontools and s6 supervision systems through a unified interface.