feat: support dodged and stacked bar plots using maidr-ts

[dakshpokar]

Description

This PR adds support for Dodged and Stacked Bar plots using maidr ts engine.
Please merge this PR after merging: #153.
Also, merging this PR means we can't use JavaScript engine for Dodged and Stacked Bar Plots.

Type of Change

• Bug fix
• New feature
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

Additional Notes

[Copilot]

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (4)

maidr/core/plot/lineplot.py:45

• The _get_selector method now returns a list instead of a string; please ensure that any downstream code that consumes this selector is updated in accordance with the new return type.

def _get_selector(self) -> list[str]:

maidr/core/plot/grouped_barplot.py:54

• The refactoring now accumulates data in a nested list (container_data) before appending to the outer list. Verify that this new nested structure is consistent with how grouped bar data is consumed downstream.

container_data.append({

maidr/core/maidr.py:168

• Since the MaidrKey enum now maps SELECTOR to "selectors", please confirm that the schema replacement logic correctly handles both string and list values without introducing inconsistencies in the final schema.

if isinstance(schema[MaidrKey.SELECTOR], str):

example/count/example_count_plot.ipynb:95

• [nitpick] The notebook metadata version was altered from 3.12.6 to 3.10.12; please verify that this downgrade is intentional and does not conflict with other package version dependencies.

"version": "3.10.12"