The homeserver only reads appservice registrations on startup, and the
playbook only restarts it at the very end of a run. On the run which
first enables Meowlnir, bot provisioning therefore talked to a
homeserver still running without Meowlnir's registration, hitting
M_UNKNOWN_TOKEN and hanging indefinitely.

Provisioning now verifies the token upfront and restarts the homeserver
itself when needed, so a single run completes even when Meowlnir was
just enabled.

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