feat: Use column layout in items palette

[pan-kot]

Description

Introduces column layout to board items palette to fit more items when there is enough horizontal space in both side and bottom orientations of the panel.

Rel: [4xTcAv3PK6h2]

How has this been tested?

• Manual testing in test pages and demos

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 93.99%. Comparing base (4a5fb2a) to head (3449e46).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #331      +/-   ##
==========================================
+ Coverage   93.94%   93.99%   +0.04%     
==========================================
  Files          61       61              
  Lines        4312     4312              
  Branches      740      528     -212     
==========================================
+ Hits         4051     4053       +2     
+ Misses        261      259       -2     

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