fix(toc): highlight toc entries pointing to index.html

[GitToTheHub]

• Menu entries pointing to a index.html like Creating an App - guide/cli/index.html weren't being highlighted or scrolled to, whereas entries pointing to a named html page like Installation - guide/cli/installation.html were highlighted
• Normalize URLs to handle Jekyll's pretty URLs like path/ vs TOC entry URLs like path/index.html for proper comparison
• Add validation to prevent false matches on pages without URLs
• Fixes: Menu entries without sub entries should be highlighted and scrolled to #1417
• Fixed for Desktop toc_recursive_main.html‎ and Mobile toc_recursive_dropdown.html. On mobile this cannot visually be seen, since the css is not properly configured for the dropdown. This will be fixed with fix(mobile): css highlighting was only be done for desktop #1472.
• Generated-By: Claude Sonnet 4.5

Platforms affected

Motivation and Context

Description

Testing

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[GitToTheHub]

This is ready to review