feat: server-side OAuth token management system

Co-Authored-By: Classic298 <27028174+Classic298@users.noreply.github.com>

backend/open_webui/migrations/versions/38d63c18f30f_add_oauth_session_table.py

@@ -0,0 +1,52 @@
+"""Add oauth_session table
+
+Revision ID: 38d63c18f30f
+Revises: 3af16a1c9fb6
+Create Date: 2025-09-08 14:19:59.583921
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "38d63c18f30f"
+down_revision: Union[str, None] = "3af16a1c9fb6"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Create oauth_session table
+    op.create_table(
+        "oauth_session",
+        sa.Column("id", sa.Text(), nullable=False),
+        sa.Column("user_id", sa.Text(), nullable=False),
+        sa.Column("provider", sa.Text(), nullable=False),
+        sa.Column("token", sa.Text(), nullable=False),
+        sa.Column("expires_at", sa.BigInteger(), nullable=False),
+        sa.Column("created_at", sa.BigInteger(), nullable=False),
+        sa.Column("updated_at", sa.BigInteger(), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+        sa.ForeignKeyConstraint(["user_id"], ["user.id"], ondelete="CASCADE"),
+    )
+
+    # Create indexes for better performance
+    op.create_index("idx_oauth_session_user_id", "oauth_session", ["user_id"])
+    op.create_index("idx_oauth_session_expires_at", "oauth_session", ["expires_at"])
+    op.create_index(
+        "idx_oauth_session_user_provider", "oauth_session", ["user_id", "provider"]
+    )
+
+
+def downgrade() -> None:
+    # Drop indexes first
+    op.drop_index("idx_oauth_session_user_provider", table_name="oauth_session")
+    op.drop_index("idx_oauth_session_expires_at", table_name="oauth_session")
+    op.drop_index("idx_oauth_session_user_id", table_name="oauth_session")
+
+    # Drop the table
+    op.drop_table("oauth_session")