write a simple transmitting emulator

[shira6]

imitate a single device that connects over TCP and sends telemetry once every second.
make sure the basic flow works from the emulator into Node-RED and to the rest of the workflow.
The emulator should:

• connect to a configurable host/port
• send JSON messages repeatedly
• include a device id, timestamp, and some random/sample value
• print what it sends so debugging is easier

Example message:

{
"device_id": "dev_001",
"timestamp": "2026-05-14T10:00:00Z",
"value": 42.5
}