Replace office Raspberry Pi power supply/cable and verify USB stability

## Goal

Correct the office Raspberry Pi undervoltage condition before adding more USB workloads or running a production Z-Wave radio service.

## Current evidence

- `vcgencmd get_throttled` returned `0x50005`, indicating active undervoltage and throttling plus historical occurrences.
- Kernel logs recorded undervoltage before the Z-Wave stick was attached, so the existing supply or micro-USB power cable was already marginal.
- After attaching the Aeotec Z-Stick, the USB serial device disconnected and reconnected twice before appearing as `/dev/ttyACM0`.
- The Eaton UPS USB connection remained detected.

## Task for September 13, 2026

- [ ] Replace the micro-USB power cable and/or supply with a known-good, short cable and a reliable 5.1 V, 2.5 A source.
- [ ] If additional USB peripherals remain unstable, use a quality externally powered USB hub.
- [ ] Power-cycle the Pi cleanly.
- [ ] Confirm `vcgencmd get_throttled` returns `0x0`.
- [ ] Review recent kernel messages for new undervoltage or USB reset/disconnect events.
- [ ] Confirm the Eaton UPS and Aeotec Z-Stick remain present continuously for at least 10 minutes.
- [ ] Only then proceed with the Z-Wave JS radio-host deployment.

## Acceptance criteria

The Pi runs without current or historical throttling flags following the clean power cycle, and both USB devices remain stable without reconnect events during the observation window.

Start with the office Raspberry Pi power supply and micro-USB cable, then power-cycle the device cleanly. Run `vcgencmd get_throttled` and review recent kernel messages for undervoltage or USB reset events; verify the Eaton UPS and Aeotec Z-Stick stay present for at least 10 minutes. Done means throttling reports `0x0` and neither USB device reconnects during observation.

Written by the indexing model from the issue text.