The panel health probe tests the global plugin config only. When the
plugin is enabled as a master switch with no global API key (users supply
their own), the probe reported a hard "down", which read as broken.
Return "degraded" with an explanatory detail instead — a keyless master
switch is a valid setup, nothing is failing. The Web App user-facing path
is unchanged: a caller whose effective key is empty still gets "down" with
an actionable "add one to connect" message before the plugin is called.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
