Refines the previous commit's doc fix with more precise, hardware-
verified detail: the ST20 doesn't just silently drop the connection --
its own firmware ("AllegroWebserver") eventually returns an explicit
"AllegroWebserver timeout: /getGroup" plain-text error after an
internal delay of several+ seconds, well past what client.get()'s
timeout will tolerate.
Also documents a dead-end a future contributor might otherwise try:
the ST20's own /supportedURLs response lists /getGroup (and the other
group endpoints) despite not actually servicing it, confirmed against
the same real hardware. A supportedURLs-based capability probe would
not have caught this either -- the model-name check has to stay.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>