Checkpoint React frontend migration

backend/alembic/versions/20260617_000005_session_expires_at.py

@@ -0,0 +1,26 @@
+"""add session expires at
+
+Revision ID: 20260617_000005
+Revises: 20260405_000004
+Create Date: 2026-06-17 15:00:00
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = "20260617_000005"
+down_revision: Union[str, None] = "20260405_000004"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column("sessions", sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("sessions", "expires_at")