Step 7 (ntfy ban alerts) always defaulted straight to the public
ntfy.sh, regardless of whether the box (or a homelab) already had a
real ntfy instance. Confusing in practice: this step runs before
asterisk-do's own ntfy extra is dispatched, so even selecting it
wouldn't have helped at prompt time.
Now checks the local ntfy install's own config/server.yml for a
configured base-url (skipping it if it's still the ntfy.sh-written
placeholder) and uses <base-url>/crowdsec-alerts as the default. If
there's no configured local instance, it says so explicitly and
prompts toward a hosted instance elsewhere (e.g. a homelab) instead of
silently assuming the public service. Verified all three cases
(configured local, unconfigured placeholder, none) in isolation, plus
a full regression run.