feat: support heatmap and also highlight in py-maidr using maidr-ts

[dakshpokar]

Description

This PR adds support for heatmap in py-maidr using maidr-ts.
Note that we need to merge this PR after merging: #153.
Also furthermore, once this PR is merged we will be deprecating support for heatmap using maidr js. So the only way to have heatmap with maidr support in py-maidr is to use maidr ts.

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 13 out of 13 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

maidr/core/maidr.py:169

• [nitpick] Consider using a clearer iteration method such as 'for index, sel in enumerate(schema[MaidrKey.SELECTOR])' to improve code readability when updating each selector string.

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