Add basis workspace filters, stale-on-reimport, and variant usage metrics

app/models/item.py

@@ -155,6 +155,39 @@ class Item(Base):
         nullable=True,
         comment="Original item ID (for AI variants)",
     )
+    generation_run_id: Mapped[Union[int, None]] = mapped_column(
+        ForeignKey("ai_generation_runs.id", ondelete="SET NULL", onupdate="CASCADE"),
+        nullable=True,
+        index=True,
+        comment="AI generation run ID",
+    )
+    source_snapshot_question_id: Mapped[Union[int, None]] = mapped_column(
+        ForeignKey("tryout_snapshot_questions.id", ondelete="SET NULL", onupdate="CASCADE"),
+        nullable=True,
+        index=True,
+        comment="Source snapshot question ID",
+    )
+    variant_status: Mapped[str] = mapped_column(
+        String(50),
+        nullable=False,
+        default="active",
+        comment="Lifecycle status (active/draft/approved/rejected/archived/stale)",
+    )
+    reviewed_by: Mapped[Union[str, None]] = mapped_column(
+        String(255),
+        nullable=True,
+        comment="Reviewer username",
+    )
+    reviewed_at: Mapped[Union[datetime, None]] = mapped_column(
+        DateTime(timezone=True),
+        nullable=True,
+        comment="Review timestamp",
+    )
+    review_notes: Mapped[Union[str, None]] = mapped_column(
+        Text,
+        nullable=True,
+        comment="Review notes",
+    )
 
     # Timestamps
     created_at: Mapped[datetime] = mapped_column(
@@ -187,6 +220,11 @@ class Item(Base):
         lazy="selectin",
         cascade="all, delete-orphan",
     )
+    generation_run: Mapped[Union["AIGenerationRun", None]] = relationship(
+        "AIGenerationRun",
+        back_populates="generated_items",
+        lazy="selectin",
+    )
 
     # Constraints and indexes
     __table_args__ = (
@@ -203,10 +241,11 @@ class Item(Base):
             "website_id",
             "slot",
             "level",
-            unique=True,
+            unique=False,
         ),
         Index("ix_items_calibrated", "calibrated"),
         Index("ix_items_basis_item_id", "basis_item_id"),
+        Index("ix_items_variant_status", "variant_status"),
         # IRT b parameter constraint [-3, +3]
         CheckConstraint(
             "irt_b IS NULL OR (irt_b >= -3 AND irt_b <= 3)",