Transitions: Link to a browser extension in assignment section

[Maddily]

Added a link to the CSS Stacking Context inspector browser extension. The ‘i’ in ‘inspector’ is lowercase to match the name as it appears on the Chrome Web Store.

Because

The browser extension helps learners visualize stacking contexts on a page, making it easier to understand layout and repaint behavior.

This PR

• Adds an assignment to try out the CSS Stacking Context inspector browser extension.

Issue

Closes #28566

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide