- 新建 df-storage/migrations_helpers.rs(103行): column_exists纯查询fn + 4测试 - migrations.rs 659→541: use column_exists + 删原fn+测试, run/migrate_v1-v19主入口保留 - lib.rs: pub mod migrations_helpers 主代grep核验(不cargo避executor-split df-workflow中间态): migrations.rs use+column_exists 16处调用 + lib.rs pub mod印证; agent df-storage独立自验cargo 0+test 35+11 strategy: 核心库自底向上, 纯查询函数抽离(PRAGMA无副作用, SQL行为不变), pub(crate)零外部暴露扩大 git add指定(df-storage/*)