fix(db): resolve invariant model migration head

src/cleveragents/infrastructure/database/migrations/versions/m11_001_standalone_invariants.py

@@ -8,7 +8,7 @@ separate from action-level (``action_invariants``) and plan-level
 CLI invocations even when not attached to a specific action or plan.
 
 Revision ID: m11_001_standalone_invariants
-Revises: m9_003_plan_result_success_column
+Revises: m9_004_merge_invariants_branch
 Create Date: 2026-05-12 00:00:00
 
 """
@@ -18,7 +18,7 @@ from alembic import op
 
 # revision identifiers, used by Alembic.
 revision: str = "m11_001_standalone_invariants"
-down_revision: str | None = "m9_003_plan_result_success_column"
+down_revision: str | None = "m9_004_merge_invariants_branch"
 branch_labels: str | None = None
 depends_on: str | None = None
 

src/cleveragents/infrastructure/database/models.py

@@ -3785,35 +3785,3 @@ class IndexedFileModel(Base):
         Index("ix_indexed_files_language", "language"),
     )
 
-
-# ---------------------------------------------------------------------------
-# Invariant Models (Stage M3 - invariant management, issue #8524)
-# ---------------------------------------------------------------------------
-
-
-class InvariantModel(Base):  # type: ignore[misc]
-    """Database model for globally-scoped invariants.
-
-    Invariants are user-defined constraints that must hold true across all
-    planning sessions.  Each row represents a single invariant rule with
-    its description, creation timestamp, and active status.
-
-    Table: ``invariants``
-    """
-
-    __allow_unmapped__ = True
-    __tablename__ = "invariants"
-
-    # PK: UUID stored as a 36-character string
-    id = Column(String(36), primary_key=True)
-
-    # Human-readable description of the invariant constraint
-    description = Column(Text, nullable=False)
-
-    # Timestamp of creation (ISO-8601 string, UTC)
-    created_at = Column(String(30), nullable=False)
-
-    # Whether this invariant is currently active (default True)
-    is_active = Column(Boolean, nullable=False, default=True, server_default="1")
-
-    __table_args__ = (Index("ix_invariants_is_active", "is_active"),)