feat: Add prefix and secondaryText to Token

[NathanZlion]

Description

Adds two props to Token, per the Token additions API proposal:

• prefix: an aria-hidden slot before the label, for example a category color dot.
• secondaryText: a lighter value shown after the label, for example a coverage percentage.

Existing tokens are unchanged. The new dev page token/additions demos both props, the inline variant, and composing a Popover in the label slot together with prefix and secondary text. The API proposal links to this PR as the demo.

This is a draft for demo purposes. Test-utils finders and unit tests for the new props will follow.

How has this been tested?

• gulp quick-build passes locally
• Existing token unit tests pass (79/79)
• Checked visually on the dev page

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.70%. Comparing base (fc0c496) to head (c30ae11).
⚠️ Report is 79 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5090      +/-   ##
==========================================
+ Coverage   97.66%   97.70%   +0.03%     
==========================================
  Files         959      989      +30     
  Lines       31340    31791     +451     
  Branches    11578    11738     +160     
==========================================
+ Hits        30609    31062     +453     
- Misses        685      722      +37     
+ Partials       46        7      -39     

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