fix(sec): warn when deferred imports stay stale

app/models/data_import_run.py

@@ -40,4 +40,5 @@ class DataImportRun(Base):
     completed_at: Mapped[datetime | None] = mapped_column(
         DateTime(timezone=True), nullable=True
     )
+    # Failure detail, or the non-error reason when status is deferred.
     error_details: Mapped[str | None] = mapped_column(Text, nullable=True)