chore: Apply one-theme panel colors

[at-susie]

Description

This PR updates panel color and shadow tokens for one-theme.
Adds shadow tokens and panel color support to the one-theme style dictionary, and updates app-layout component styles to use the new tokens.

Related links, issue #, if available: n/a

How has this been tested?

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 97.51%. Comparing base (23d2b6f) to head (cf54816).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4598   +/-   ##
=======================================
  Coverage   97.51%   97.51%           
=======================================
  Files         948      948           
  Lines       30328    30328           
  Branches    11055    11055           
=======================================
  Hits        29574    29574           
  Misses        747      747           
  Partials        7        7           

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