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