Warn users that using `.query` blocks optimizations and suggest better alternatives

`.query` blocks optimizations like predicate and filter pushdown. Once we implemented column expressions, we should add a warning that makes users aware of this and suggests better alternatives to using `.query`

Start by locating the `.query` implementation and the column-expression code mentioned in the issue, then inspect existing tests for query behavior and optimization. Done means users receive a warning explaining that `.query` blocks predicate and filter pushdown and pointing them toward better alternatives.

Written by the indexing model from the issue text.