ALTER TABLE sessions ADD COLUMN model_with_qwen TEXT
    CHECK (model_with_qwen IS NULL OR model_with_qwen IN (
        'deepseek-v4-flash-0731',
        'deepseek-v4-pro',
        'glm-5.2',
        'glm-5.3-flash',
        'qwen3.8-flash-next'
    ));
UPDATE sessions SET model_with_qwen = model;
ALTER TABLE sessions DROP COLUMN model;
ALTER TABLE sessions RENAME COLUMN model_with_qwen TO model;
