M24: implement privacy governance

backend/app/models/customer.py

@@ -1,7 +1,7 @@
 import uuid
-from datetime import date
+from datetime import date, datetime
 
-from sqlalchemy import Date, ForeignKey, String
+from sqlalchemy import Date, DateTime, ForeignKey, String
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import Mapped, mapped_column
 
@@ -23,3 +23,4 @@ class Customer(UUIDPrimaryKeyMixin, TimestampMixin, Base):
     merged_into_customer_id: Mapped[uuid.UUID | None] = mapped_column(
         UUID(as_uuid=True), ForeignKey("customers.id")
     )
+    anonymized_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))