Add migration for device_id column on oauth_grants

The column was added to the create_table migration after it had already
been applied, so the live DB was missing it.  This new migration adds
the column and index separately.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

alembic/versions/r8p6m2n4o5_add_device_id_to_oauth_grants.py

@@ -0,0 +1,29 @@
+"""Add device_id column to oauth_grants
+
+Revision ID: r8p6m2n4o5
+Revises: q7o5l1m3n4
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "r8p6m2n4o5"
+down_revision = "q7o5l1m3n4"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # device_id was added to the create_table migration after it had already
+    # run, so the column is missing from the live DB.  Add it now.
+    op.add_column(
+        "oauth_grants",
+        sa.Column("device_id", sa.String(128), nullable=True),
+    )
+    op.create_index(
+        "ix_oauth_grant_device", "oauth_grants", ["device_id", "client_id"]
+    )
+
+
+def downgrade():
+    op.drop_index("ix_oauth_grant_device", table_name="oauth_grants")
+    op.drop_column("oauth_grants", "device_id")