Add systemd-style subcommands for managing KVS instances:
- start <config> - Daemonize and run in background
- stop <config> - Gracefully stop daemon
- restart <config> - Restart daemon
- status [config] - Show status of all or specific instances
Key features:
- PID files stored in ~/.kvs/pids/ (global across all directories)
- Logs stored in ~/.kvs/logs/
- Config names support both 'node1' and 'node1.yaml' formats
- Backward compatible: 'kvs config.yaml' still runs in foreground
- Proper stale PID detection and cleanup
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
