fix(invariant): extract InvariantRepository to dedicated module and fix formatting

- Remove InvariantRepository class from repositories.py (was duplicated)
- Add re-export from invariant_repository.py for backward compatibility
- Fix ruff formatting issue in InvariantModel (non_overridable column)
- All quality gates passing: lint, format, typecheck, security

ISSUES CLOSED: #8573

src/cleveragents/infrastructure/database/models.py

@@ -1307,9 +1307,7 @@ class InvariantModel(Base):  # type: ignore[misc]
     scope = Column(String(20), nullable=False)
     source_name = Column(String(255), nullable=False)
     active = Column(Boolean, nullable=False, default=True, server_default="1")
-    non_overridable = Column(
-        Boolean, nullable=False, default=False, server_default="0"
-    )
+    non_overridable = Column(Boolean, nullable=False, default=False, server_default="0")
     created_at = Column(String(30), nullable=False)
 
     def to_domain(self) -> Invariant:

src/cleveragents/infrastructure/database/repositories.py

@@ -112,7 +112,6 @@ from cleveragents.infrastructure.database.models import (
     CorrectionAttemptModel,
     DebugAttemptModel,
     DecisionModel,
-    InvariantModel,
     LifecycleActionModel,
     LifecyclePlanModel,
     NamespacedProjectModel,
@@ -141,8 +140,6 @@ if TYPE_CHECKING:
         CorrectionAttemptRecord,
     )
     from cleveragents.domain.models.core.decision import Decision
-    from cleveragents.domain.models.core.invariant import Invariant
-
 
 from cleveragents.domain.models.core.correction import (
     CORRECTION_ATTEMPT_TERMINAL_STATES,
@@ -6091,144 +6088,11 @@ class CorrectionAttemptRepository:
 
 
 # ---------------------------------------------------------------------------
-# InvariantRepository — Standalone Invariant Persistence
+# InvariantRepository -- re-exported from dedicated module
 # ---------------------------------------------------------------------------
-
-
-class InvariantRepository:
-    """Repository for standalone invariant persistence.
-
-    Implements CRUD operations for invariants with database backing,
-    enabling invariants to persist across process restarts.
-
-    Uses a session-factory pattern: each public method obtains its own
-    session from the factory, ensuring proper session lifecycle management.
-
-    All mutating methods flush (but do NOT commit); the caller or a
-    ``UnitOfWork`` wrapper is responsible for committing the transaction.
-    """
-
-    def __init__(self, session_factory: Callable[[], Session]) -> None:
-        """Initialise with a callable that returns a new SQLAlchemy Session."""
-        self._session_factory = session_factory
-
-    def _session(self) -> Session:
-        """Convenience helper to obtain a session."""
-        return self._session_factory()
-
-    @database_retry
-    def add(self, invariant: Invariant) -> Invariant:
-        """Persist a new invariant to the database.
-
-        Args:
-            invariant: An ``Invariant`` domain model instance.
-
-        Returns:
-            The same ``Invariant`` after persistence.
-
-        Raises:
-            DatabaseError: On transient or unexpected DB errors.
-        """
-
-        session = self._session()
-        try:
-            db_model = InvariantModel.from_domain(invariant)
-            session.add(db_model)
-            session.flush()
-            session.commit()
-            return invariant
-        except (OperationalError, SQLAlchemyDatabaseError) as exc:
-            session.rollback()
-            raise DatabaseError(f"Failed to add invariant: {exc}") from exc
-
-    @database_retry
-    def list(
-        self,
-        scope: str | None = None,
-        source_name: str | None = None,
-    ) -> list[Invariant]:
-        """List invariants, optionally filtered by scope and/or source_name.
-
-        Args:
-            scope: Filter by scope (None = all scopes).
-            source_name: Filter by source name (None = all sources).
-
-        Returns:
-            List of ``Invariant`` domain objects.
-
-        Raises:
-            DatabaseError: On transient or unexpected DB errors.
-        """
-        session = self._session()
-        try:
-            query = session.query(InvariantModel).filter_by(active=True)
-
-            if scope is not None:
-                query = query.filter_by(scope=scope)
-
-            if source_name is not None:
-                query = query.filter_by(source_name=source_name)
-
-            rows = query.all()
-            return [row.to_domain() for row in rows]
-        except (OperationalError, SQLAlchemyDatabaseError) as exc:
-            raise DatabaseError(f"Failed to list invariants: {exc}") from exc
-
-    @database_retry
-    def get_by_id(self, invariant_id: str) -> Invariant | None:
-        """Retrieve an invariant by its ULID.
-
-        Args:
-            invariant_id: The ULID of the invariant.
-
-        Returns:
-            The ``Invariant`` domain object, or ``None`` if not found.
-
-        Raises:
-            DatabaseError: On transient or unexpected DB errors.
-        """
-        session = self._session()
-        try:
-            row = session.query(InvariantModel).filter_by(id=invariant_id).first()
-            if row is None:
-                return None
-            return row.to_domain()
-        except (OperationalError, SQLAlchemyDatabaseError) as exc:
-            raise DatabaseError(
-                f"Failed to get invariant {invariant_id}: {exc}"
-            ) from exc
-
-    @database_retry
-    def soft_delete(self, invariant_id: str) -> Invariant:
-        """Soft-delete an invariant by setting active=False.
-
-        Args:
-            invariant_id: The ULID of the invariant to delete.
-
-        Returns:
-            The updated ``Invariant`` domain object.
-
-        Raises:
-            DatabaseError: On transient or unexpected DB errors.
-        """
-        from cleveragents.core.exceptions import NotFoundError
-
-        session = self._session()
-        try:
-            row = session.query(InvariantModel).filter_by(id=invariant_id).first()
-            if row is None:
-                raise NotFoundError(
-                    resource_type="invariant",
-                    resource_id=invariant_id,
-                )
-            row.active = False  # type: ignore[assignment]
-            session.flush()
-            session.commit()
-            return row.to_domain()
-        except NotFoundError:
-            raise
-        except (OperationalError, SQLAlchemyDatabaseError) as exc:
-            session.rollback()
-            raise DatabaseError(
-                f"Failed to soft-delete invariant {invariant_id}: {exc}"
-            ) from exc
+# InvariantRepository has been extracted into its own module to keep
+# repositories.py focused. The re-export below preserves backward
+# compatibility for existing imports.
+from cleveragents.infrastructure.database.invariant_repository import (  # noqa: E402, F401
+    InvariantRepository,
+)