HTTP config-mutating endpoints (publish, rollback, channel CRUD, user
self-update) were calling config.reload() directly, which only refreshed
the in-memory config dict. This skipped re-applying host.dyn/host.watched
flags to live Host objects, so enabling dyndns via the UI had no effect
until a SIGHUP was sent.
Wire a reload_callback through http.start() that calls the same
reload_configuration() function used by the SIGHUP handler, ensuring
host attributes, notify module, users, and threshold checker are all
updated on every config publish.
Also fix unmatched quote in udp.py f-string log message.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>