Support for pd.col, newly added in Pandas 3

**Feature request**
Pandas introduced `col` in v3, which is a method that represents a column of a dataframe in operations like assignment.
https://pandas.pydata.org/docs/reference/api/pandas.col.html

We should investigate out of the box compatibility with nested columns, and see what if anything we would like to build on top of col for custom support of nested structures.
**Before submitting**
Please check the following:

- [x] I have described the purpose of the suggested change, specifying what I need the enhancement to accomplish, i.e. what problem it solves.
- [x] I have included any relevant links, screenshots, environment information, and data relevant to implementing the requested feature, as well as pseudocode for how I want to access the new functionality.
- [] If I have ideas for how the new feature could be implemented, I have provided explanations and/or pseudocode and/or task lists for the steps.

Start with the linked pandas.col documentation and investigate how nested-pandas currently handles nested columns and dataframe assignment. Determine whether pandas 3 compatibility works out of the box and document or implement any needed custom support for nested structures; done should include an agreed behavior and coverage for the relevant cases.

Written by the indexing model from the issue text.