Admin routes: uncomplete and regenerate

The admin plane could reverse nothing and re-materialize nothing: a
mis-tapped completion could only be fixed by hand in the database, and
a config or presence change left the household's rolling horizon
stale until the integration itself regenerated it.

- POST /api/v1/admin/instances/{id}/uncomplete appends the reversal
  through core uncomplete_instance (actor_source 'user' with the
  verified JWT's sub — D-008), so the original completed row is never
  edited or deleted and the derived state returns to open.  An actual
  reversal publishes the quest-uncompleted transition via the existing
  api.transitions helper; an already-open no-op publishes nothing and
  still answers with the honest derived state (open, or missed when
  past due).
- POST /api/v1/admin/regenerate re-materializes the rolling horizon
  through the same core path the integration uses: household (default)
  = materialize over [today, today + const.DEFAULT_HORIZON_DAYS] (the
  API config supplies no horizon knob), definition/child =
  regenerate_for_definition / regenerate_for_child after ONE DAO
  existence read each (unknown id -> 404, which the core's regenerate
  path itself does not check).  The walk is idempotent, so re-running
  never duplicates an instance.

Both handlers are thin adapters: Pydantic models carry the request
shape (scope/id pairing is the model's job), the business rules stay
in core, and the error mapping stays narrow — unknown
instance/definition/child 404, rejected argument 422, anything else
re-raises.

api/nestquest_core.py

@@ -161,13 +161,38 @@ core_dao_presence = importlib.import_module(
     f"{_CORE_MODULE_NAME}.dao_presence"
 )
 
+#: The materialization walk (``core.materialize.materialize``,
+#: ``regenerate_for_definition``, ``regenerate_for_child``) the admin
+#: plane's regenerate route calls — the same walk the integration's
+#: config/presence changes trigger.
+core_materialize = importlib.import_module(f"{_CORE_MODULE_NAME}.materialize")
+
+#: The core constants module (``core.const.DEFAULT_HORIZON_DAYS``) the
+#: regenerate route sizes the household rolling horizon with.
+core_const = importlib.import_module(f"{_CORE_MODULE_NAME}.const")
+
+#: The typed child DAO (``core.dao_children.ChildrenDao.get``) the
+#: regenerate route reads a child's existence with before delegating.
+core_dao_children = importlib.import_module(
+    f"{_CORE_MODULE_NAME}.dao_children"
+)
+
+#: The typed definition DAO (``core.dao_rules.QuestDefinitionsDao.get``)
+#: the regenerate route reads a definition's existence with before
+#: delegating.
+core_dao_rules = importlib.import_module(f"{_CORE_MODULE_NAME}.dao_rules")
+
 __all__ = [
     "core",
     "core_children",
     "core_completion",
+    "core_const",
+    "core_dao_children",
     "core_dao_presence",
+    "core_dao_rules",
     "core_db",
     "core_events",
+    "core_materialize",
     "core_migrations",
     "core_presence",
     "core_presence_management",