Implemented the 'peer ping' command by establishing an IPC mechanism between the CLI and the running 'node serve' process.
- Added 'ControlService' in 'pkg/node' exposing RPC methods over a Unix socket.
- Implemented 'MessageDispatcher' to route P2P messages to 'Controller' (responses) or 'Worker' (requests).
- Updated 'node serve' to start the IPC server and use the dispatcher.
- Updated 'peer ping' to use the IPC client to request pings from the running node.
- Fixed broken 'pkg/node/dispatcher.go' file.
