niwaki v1.3.0

Native APIC object-subscription: a query becomes a live push stream instead
of a one-off read, over the same WebSocket mechanism the APIC GUI itself
uses. Purely additive — the configuration API and the query surface are
unchanged.

Added

• Query.subscribe() / AsyncQuery.subscribe(). Any single-class query
  can be subscribed instead of fetched: .initial gives the synchronous
  snapshot, then the returned Subscription/AsyncSubscription iterates
  live push events for as long as it stays open. One shared WebSocket per
  session multiplexes every subscription; refresh and reconnect run
  automatically in the background — nothing here needs a caller-driven loop.

• Typed events. Each item is a SubscriptionEvent: .kind
  (EventKind.CREATED/MODIFIED/DELETED/GAP/REFRESH_FAILED), .mo
  deserialised through the same readable field names a normal read uses,
  with .mo.model_fields_set reporting exactly what that push carried (the
  APIC sends sparse deltas on MODIFIED, dn only on DELETED).

• Automatic recovery, never silent. The APIC has no replay mechanism at
  all, so a reconnect resubscribes everything from scratch and delivers a
  GAP event rather than continuing as if nothing happened. Two consecutive
  missed refreshes trigger the same kind of recovery for that one
  subscription. SubscriptionLostError — with .reason — is raised only
  once recovery itself has been tried and failed.

• Bulk and single-subscription tools. aci.subscriptions.list() /
  .refresh_all() / .close_all() manage every subscription open on a
  session at once (close_all() stops them without tearing down the shared
  socket); sub.info / sub.refresh_now() do the same for one subscription.

• Validated live against a real fabric: genuine create/modify/delete push
  payloads, a real subscriptionId, and the subscriptionRefresh endpoint
  accepting a real id.