feat: 支持按权益名称导入用户

ai_knowledge_base_v2/apps/backend/app/services/entitlement_service.py

@@ -312,6 +312,41 @@ class EntitlementService:
         )
         return entitlement
 
+    @staticmethod
+    def clear_user_plan(
+        db: Session,
+        *,
+        user: User,
+        operated_by: int | None,
+        reason: str | None = None,
+    ) -> None:
+        """Remove explicit entitlements so the user returns to the unassigned/default state."""
+        current_rows = list(
+            db.scalars(
+                select(UserEntitlement)
+                .where(UserEntitlement.user_id == user.id, UserEntitlement.status == "active")
+                .order_by(UserEntitlement.created_at.desc(), UserEntitlement.id.desc())
+            )
+        )
+        if not current_rows:
+            return
+        for current in current_rows:
+            current.status = "replaced"
+            db.add(current)
+        latest = current_rows[0]
+        db.add(
+            UserEntitlementLog(
+                user_id=user.id,
+                entitlement_id=latest.id,
+                from_plan_id=latest.plan_id,
+                to_plan_id=None,
+                action="clear",
+                detail_json=json.dumps({"reason": reason}, ensure_ascii=False),
+                operated_by=operated_by,
+                created_at=_now(),
+            )
+        )
+
 
 def plan_dict(plan: EntitlementPlan) -> dict:
     return {