Address PR #142 review: core isolation invariant and shim fixes

- Point recurrence purity scan at custom_components.nestquest.core.recurrence
  (P2.1); the shim only re-exports, so the real model was no longer scanned.
- Make test_const/test_config_flow/test_dao_matrix module scans recursive
  (rglob) so custom_components/nestquest/core/ is covered (P2.2, P2.3);
  const.py name exclusion retained.
- Add test_core_isolation: AST-scan every core module for homeassistant
  imports, relative imports climbing out of core (level > 1), absolute
  imports reaching custom_components.nestquest.<not core>, and bare
  'import core'/'from core' (P2.4).
- Drop the private re-export of _month_end/_nth_weekday_of_month from the
  recurrence shim; those are test-only, so move the two test imports to
  custom_components.nestquest.core.recurrence (P2.1/P3.1).
- Fix shim docstrings and core/__init__.py to reference
  custom_components.nestquest.core.* instead of the unimportable 'core.*'
  paths (P3.2).
- Note the migrations logger namespace move to
  custom_components.nestquest.core.migrations in RELEASE_NOTES.md (P3.3).

custom_components/nestquest/const.py

@@ -1,6 +1,6 @@
-"""Re-export of :mod:`core.const` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.const` for the integration package.
 
-The canonical constants live in :mod:`core.const` (the storage layer
+The canonical constants live in :mod:`custom_components.nestquest.core.const` (the storage layer
 extracted in task d0b691d8); this module re-exports them so existing
 ``from .const import ...`` references inside the integration keep
 working without touching every import line.

custom_components/nestquest/core/__init__.py

@@ -5,7 +5,7 @@ SQLite storage layer: schema DDL, the versioned migration runner, the
 async connection wrapper, the path resolver, the domain constants and
 recurrence model, and the typed DAOs.  Nothing in this package imports
 ``homeassistant``; the integration wires it into HA at its own layer
-(constructing :class:`core.db.NestQuestDatabase` with an executor
-adapter backed by ``hass.async_add_executor_job``).
+(constructing :class:`custom_components.nestquest.core.db.NestQuestDatabase`
+with an executor adapter backed by ``hass.async_add_executor_job``).
 """
 from __future__ import annotations

custom_components/nestquest/dao_children.py

@@ -1,6 +1,7 @@
-"""Re-export of :mod:`core.dao_children` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.dao_children` for the integration package.
 
-The children/admin DAO lives in :mod:`core.dao_children` (extracted in
+The children/admin DAO lives in
+:mod:`custom_components.nestquest.core.dao_children` (extracted in
 task d0b691d8); this module re-exports it so existing
 ``from .dao_children import ...`` references inside the integration keep
 working.

custom_components/nestquest/dao_instances.py

@@ -1,6 +1,7 @@
-"""Re-export of :mod:`core.dao_instances` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.dao_instances` for the integration package.
 
-The instances/completion-events DAO lives in :mod:`core.dao_instances`
+The instances/completion-events DAO lives in
+:mod:`custom_components.nestquest.core.dao_instances`
 (extracted in task d0b691d8); this module re-exports it so existing
 ``from .dao_instances import ...`` references inside the integration keep
 working.

custom_components/nestquest/dao_meta.py

@@ -1,6 +1,7 @@
-"""Re-export of :mod:`core.dao_meta` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.dao_meta` for the integration package.
 
-The meta-state DAO lives in :mod:`core.dao_meta` (extracted in task
+The meta-state DAO lives in
+:mod:`custom_components.nestquest.core.dao_meta` (extracted in task
 d0b691d8); this module re-exports it so existing
 ``from .dao_meta import ...`` references inside the integration keep
 working.

custom_components/nestquest/dao_presence.py

@@ -1,7 +1,8 @@
-"""Re-export of :mod:`core.dao_presence` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.dao_presence` for the integration package.
 
-The presence DAOs live in :mod:`core.dao_presence` (extracted in task
-d0b691d8); this module re-exports them so existing
+The presence DAOs live in
+:mod:`custom_components.nestquest.core.dao_presence` (extracted in
+task d0b691d8); this module re-exports them so existing
 ``from .dao_presence import ...`` references inside the integration keep
 working.
 """

custom_components/nestquest/dao_rules.py

@@ -1,9 +1,10 @@
-"""Re-export of :mod:`core.dao_rules` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.dao_rules` for the integration package.
 
 The schedule-rules/quest-definitions DAO lives in
-:mod:`core.dao_rules` (extracted in task d0b691d8); this module
-re-exports it so existing ``from .dao_rules import ...`` references
-inside the integration keep working.
+:mod:`custom_components.nestquest.core.dao_rules` (extracted in task
+d0b691d8); this module re-exports it so existing
+``from .dao_rules import ...`` references inside the integration keep
+working.
 """
 from __future__ import annotations
 

custom_components/nestquest/db.py

@@ -1,6 +1,6 @@
-"""Re-export of :mod:`core.db` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.db` for the integration package.
 
-The async SQLite wrapper lives in :mod:`core.db` (extracted in task
+The async SQLite wrapper lives in :mod:`custom_components.nestquest.core.db` (extracted in task
 d0b691d8) and is Home-Assistant-free: :class:`NestQuestDatabase` takes
 an executor callable rather than a ``hass`` object.  This module
 re-exports it and provides :func:`make_database`, a thin adapter that

custom_components/nestquest/migrations.py

@@ -1,6 +1,7 @@
-"""Re-export of :mod:`core.migrations` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.migrations` for the integration package.
 
-The versioned migration runner lives in :mod:`core.migrations`
+The versioned migration runner lives in
+:mod:`custom_components.nestquest.core.migrations`
 (extracted in task d0b691d8); this module re-exports it so existing
 ``from .migrations import ...`` references inside the integration keep
 working.

custom_components/nestquest/recurrence.py

@@ -1,11 +1,10 @@
-"""Re-export of :mod:`core.recurrence` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.recurrence` for the integration package.
 
-The recurrence model lives in :mod:`core.recurrence` (extracted in task
-d0b691d8); this module re-exports it so existing
+The recurrence model lives in :mod:`custom_components.nestquest.core.recurrence`
+(extracted in task d0b691d8); this module re-exports it so existing
 ``from .recurrence import ...`` references inside the integration keep
 working.
 """
 from __future__ import annotations
 
 from .core.recurrence import *  # noqa: F401,F403
-from .core.recurrence import _month_end, _nth_weekday_of_month  # noqa: F401

custom_components/nestquest/schema.py

@@ -1,6 +1,7 @@
-"""Re-export of :mod:`core.schema` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.schema` for the integration package.
 
-The declarative schema DDL lives in :mod:`core.schema` (extracted in
+The declarative schema DDL lives in
+:mod:`custom_components.nestquest.core.schema` (extracted in
 task d0b691d8); this module re-exports it so existing
 ``from .schema import ...`` references inside the integration keep
 working.

custom_components/nestquest/store.py

@@ -1,7 +1,9 @@
-"""Re-export of :mod:`core.store` for the integration package.
+"""Re-export of :mod:`custom_components.nestquest.core.store` for the integration package.
 
-The path resolver lives in :mod:`core.store` (extracted in task
-d0b691d8) and is Home-Assistant-free: :func:`core.store.async_get_db_path`
+The path resolver lives in
+:mod:`custom_components.nestquest.core.store` (extracted in task
+d0b691d8) and is Home-Assistant-free:
+:func:`custom_components.nestquest.core.store.async_get_db_path`
 takes the full database path.  This module re-exports it and provides
 the original ``async_get_db_path(hass)`` signature so the integration
 resolves the path from ``hass.config.path`` exactly as before.
@@ -23,7 +25,8 @@ async def async_get_db_path(hass: HomeAssistant) -> Path:
     """Return the absolute path to the NestQuest SQLite database file.
 
     Resolves the database file from ``hass.config.path`` and delegates to
-    :func:`core.store.async_get_db_path`, which ensures the parent
-    directory exists off the event loop via :func:`asyncio.to_thread`.
+    :func:`custom_components.nestquest.core.store.async_get_db_path`,
+    which ensures the parent directory exists off the event loop via
+    :func:`asyncio.to_thread`.
     """
     return await _core_async_get_db_path(hass.config.path(SQLITE_DB_FILENAME))