fix: enforce durable migration ownership and readiness

hub_core/migrations/env.py

@@ -5,6 +5,7 @@ from alembic import context
 from sqlalchemy import engine_from_config, pool
 
 from hub_core.models import Base
+from hub_core.migrations.roles import migration_role_statement
 
 config = context.config
 
@@ -38,6 +39,8 @@ def run_migrations_online() -> None:
         poolclass=pool.NullPool,
     )
     with connectable.connect() as connection:
+        if statement := migration_role_statement(os.environ.get("HUB_CORE_MIGRATION_ROLE")):
+            connection.exec_driver_sql(statement)
         context.configure(connection=connection, target_metadata=target_metadata)
         with context.begin_transaction():
             context.run_migrations()