Implement MachineRegistry that manages machine configurations and
provides Connection instances for local and remote operations:
- Machine struct with name, type, host, key path, and town path
- Registry with JSON persistence (federation.json)
- CRUD operations: Get, Add, Remove, List
- Connection factory that returns appropriate Connection type
- Built-in "local" machine that cannot be removed
SSH connections return an error until SSHConnection is implemented.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
0013cc0f19