homebridge-dummy fails to install in HOOBS 5.1.8 with "unhandled rejection: undefined undefined"

[sghrush70]

Attempting to install the homebridge-dummy plugin through the HOOBS UI fails with:

Hubwarn unhandled rejection: undefined undefined

Manual npm install shows the real error:

TypeError: Cannot set properties of null (setting 'dev')

Environment:
HOOBS server: 5.1.8
Node: v20.5.1
npm: 9.8.0

The HOOBS UI appears to hide the underlying npm error, making troubleshooting difficult.

Removing stale bridge folders and restarting hoobsd did not resolve the issue.