- New NotifyJobRunner base class (extends netbox.jobs.JobRunner) holds
the plugin SETTINGS and the helpers shared by both NOTIFY jobs:
load_tsig_key(), send_notify() and get_soa_serial() (promoted from
the former module-level _-prefixed functions).
- SendClientNotify and SendNSNotify extend the base and access the
helpers via self. Behavior, job names and kwargs are unchanged.
- The nameserver-only helpers moved into SendNSNotify as
notify_ns_enabled() (classmethod, reads cls.SETTINGS) and
resolve_zone_nameserver_ips() (instance method).
- No changes to any callers: schedule_client_notify(),
schedule_ns_notify() and the catalog zone NOTIFY scheduling keep
their names and call sites.