chore: add yarn-berry-deduplicate script and CI task

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes Repo: integrate with yarn-berry-deduplicate for fewer dependencies tree #11216
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

💖

[typescript-eslint]

Thanks for the PR, @JoshuaKGoldberg!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit 23d5629

Command	Status	Duration	Result
nx test eslint-plugin --coverage=false	✅ Succeeded	5m 1s	View ↗
nx run-many -t lint	✅ Succeeded	3m 18s	View ↗
nx run-many -t typecheck	✅ Succeeded	2m 4s	View ↗
nx run integration-tests:test	✅ Succeeded	50s	View ↗
nx test typescript-estree --coverage=false	✅ Succeeded	21s	View ↗
nx test eslint-plugin-internal --coverage=false	✅ Succeeded	10s	View ↗
nx run types:build	✅ Succeeded	5s	View ↗
nx run generate-configs	✅ Succeeded	15s	View ↗
Additional runs (27)	✅ Succeeded	...	View ↗

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☁️ Nx Cloud last updated this comment at 2025-10-03 11:54:06 UTC

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.96%. Comparing base (b01c53e) to head (23d5629).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #11648   +/-   ##
=======================================
  Coverage   90.95%   90.96%           
=======================================
  Files         506      506           
  Lines       51433    51447   +14     
  Branches     8491     8493    +2     
=======================================
+ Hits        46783    46797   +14     
  Misses       4637     4637           
  Partials       13       13           

Flag	Coverage Δ
unittest	90.96% <ø> (+<0.01%)	⬆️

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see 3 files with indirect coverage changes

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