1. Fix order: Save to disk FIRST, then update HAProxy
- Prevents inconsistency if HAProxy update succeeds but disk write fails
- Data is preserved correctly on restart
2. Add IPv6 support
- Use Python ipaddress module instead of regex
- Now accepts both IPv4 and IPv6 addresses
3. Extract atomic_write_file() helper
- Eliminates duplicated code in save_map_file, save_servers_config, haproxy_save_state
- Single source of truth for atomic file operations
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
4c4ec24848