Address PR #143 review (CHANGES_REQUIRED)

P2.1: Point test_presence.py ISO-week scan at core.presence (the real
model since task 510c1f78); the integration's presence.py is now a
re-export shim, so scanning it was vacuous.

P2.2: Add direct core-builder unit tests to test_events.py — exact
payload key sets for completed/uncompleted/day-complete events,
was_on_time threading (True/False/None), event ordering (completed
fires before day-complete on the bus), and the four day-complete
outcomes (zero-quest day, non-today instance, partial day,
fully-cleared today). Add a shim timezone test that sets
hass.config.time_zone to a zone whose local date differs from UTC and
asserts the day-complete rule uses that local date.

P3.1: Split build_quest_completed_events into
build_quest_completed_event (single event, no day-complete state) and
build_child_day_complete_event (separate, returns the day-complete
event or None). The shim fires nestquest_quest_completed BEFORE it
reads the HA-local today and evaluates the day-complete rule,
restoring the pre-extraction ordering so a failure in the day-complete
DB reads or the ZoneInfo lookup cannot suppress the completed event.
Payloads and the day-complete rule are identical.

P3.2: test_startup_db.py glob -> rglob so core/ is scanned by the
'never unlinks or truncates DB files' guardrail (non-recursive glob
skipped the extracted core package).

P3.3: RELEASE_NOTES.md notes the children and admin_allowlist loggers
moved to .core.children / .core.admin_allowlist (parent logger still
catches them).

P3.4: Refresh the stale test_core_isolation.py docstring to cover the
whole core package (storage-layer task d0b691d8 + engines/business-
layer task 510c1f78).

uv run pytest -q = 1507 passed (baseline 1497 + 10 new).

tests/test_presence.py

@@ -364,11 +364,19 @@ def test_cycle_week_index_stable_across_three_year_boundaries() -> None:
 
 
 def test_module_uses_no_iso_week_functions() -> None:
-    """D-004 guardrail: cycle math never reads ISO week numbers."""
+    """D-004 guardrail: cycle math never reads ISO week numbers.
+
+    Scanned against ``custom_components.nestquest.core.presence`` (the
+    real presence model since task 510c1f78); the integration's
+    ``presence.py`` is now a re-export shim, so scanning the shim is
+    vacuous.  Mirrors ``test_recurrence_model.py``'s scan of
+    ``core.recurrence``.
+    """
     from pathlib import Path
 
     source = Path(
-        __import__("custom_components.nestquest.presence", fromlist=["__file__"]).__file__
+        __import__("custom_components.nestquest.core.presence",
+                   fromlist=["__file__"]).__file__
     ).read_text()
     assert "isocalendar" not in source
     assert "isoweek" not in source