Fix InvalidOperationError

✅ Solution

The "InvalidOperationError: pl.field() called outside of struct context" or related broadcasting errors often arise when Polars incorrectly infers a scalar operation within a list/struct context or attempts to broadcast a unit-length list/array as a scalar during `eval`, `with_columns`, or `with_fields` operations. To fix this, ensure that expressions explicitly handle list/struct elements using `pl.element()` or `pl.col().list.get()` within list/struct contexts, and revise broadcasting logic to correctly handle unit-length lists/arrays or avoid unnecessary broadcasting.