Asks the homeserver who Meowlnir's appservice token belongs to.
A 401 (M_UNKNOWN_TOKEN) response means the homeserver is running
without Meowlnir's appservice registration, which is the usual cause
of Meowlnir's "Failed to connect to homeserver" log messages.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>