Extract the engines and business layer into core/ (task 510c1f78)

Move presence.py, materialize.py, completion.py, events.py, children.py,
quest_definitions.py, admin_allowlist.py and service_policy.py into
custom_components/nestquest/core/, leaving re-export shims at the
original paths so the integration keeps working unchanged.

core/events.py is refactored to PAYLOAD CONSTRUCTION ONLY: it builds
and returns (event_type, payload) tuples and never touches hass.bus or
hass.config. The HA-local 'today' the day-complete rule needs is now a
parameter (read from hass.config.time_zone by the integration shim).
The events.py shim retains fire_quest_completed/fire_quest_uncompleted,
wiring the returned events to hass.bus.async_fire so the four event
names and payload shapes stay identical (nestquest_quest_completed with
was_on_time, nestquest_quest_uncompleted, nestquest_child_day_complete
with quests_due/quests_completed, occurred_at strict UTC ISO-8601).

Update two test logger-name references (children now logs as
...core.children) and the materialize _now_stamp monkeypatch target
(now patches the core module the walk reads globals from).

1497 passed (baseline). No homeassistant import under core/, no
top-level core import under the integration, no repo-root core/.

custom_components/nestquest/service_policy.py

@@ -1,46 +1,11 @@
-"""Explicit admin-only versus open service registry (Feature 09).
+"""Re-export of :mod:`custom_components.nestquest.core.service_policy` for the integration package.
 
-One mapping, one file: every registered ``nestquest`` service name is
-either ``open`` or ``admin_only``.  The permission decorator (later
-Feature 09 tasks) reads this table; it does not take per-handler
-policy arguments.
+The service policy registry lives in
+:mod:`custom_components.nestquest.core.service_policy` (extracted in
+task 510c1f78); this module re-exports it so existing
+``from .service_policy import ...`` references inside the integration
+keep working.
 """
 from __future__ import annotations
 
-from .const import (
-    DOMAIN_SERVICES,
-    SERVICE_COMPLETE_QUEST,
-    SERVICE_CREATE_PRESENCE_OVERRIDE,
-    SERVICE_CREATE_QUEST_DEFINITION,
-    SERVICE_DELETE_PRESENCE_OVERRIDE,
-    SERVICE_EXPORT_HISTORY_CSV,
-    SERVICE_MANAGE_CHILD,
-    SERVICE_REGENERATE,
-    SERVICE_SET_PRESENCE_PATTERN,
-    SERVICE_SET_QUEST_DEFINITION_ACTIVE,
-    SERVICE_UNCOMPLETE_QUEST,
-    SERVICE_UPDATE_QUEST_DEFINITION,
-)
-
-OPEN = "open"
-ADMIN_ONLY = "admin_only"
-
-SERVICE_POLICY: dict[str, str] = {
-    SERVICE_COMPLETE_QUEST: OPEN,
-    SERVICE_UNCOMPLETE_QUEST: ADMIN_ONLY,
-    SERVICE_CREATE_QUEST_DEFINITION: ADMIN_ONLY,
-    SERVICE_UPDATE_QUEST_DEFINITION: ADMIN_ONLY,
-    SERVICE_SET_QUEST_DEFINITION_ACTIVE: ADMIN_ONLY,
-    SERVICE_SET_PRESENCE_PATTERN: ADMIN_ONLY,
-    SERVICE_CREATE_PRESENCE_OVERRIDE: ADMIN_ONLY,
-    SERVICE_DELETE_PRESENCE_OVERRIDE: ADMIN_ONLY,
-    SERVICE_EXPORT_HISTORY_CSV: ADMIN_ONLY,
-    SERVICE_MANAGE_CHILD: ADMIN_ONLY,
-    SERVICE_REGENERATE: ADMIN_ONLY,
-}
-
-if frozenset(SERVICE_POLICY) != frozenset(DOMAIN_SERVICES):
-    raise RuntimeError(
-        "SERVICE_POLICY must name exactly the registered nestquest services, "
-        f"got {sorted(SERVICE_POLICY)} vs {list(DOMAIN_SERVICES)}"
-    )
+from .core.service_policy import *  # noqa: F401,F403