chore(renovate): group related dependency cohorts

[glennawatson]

What kind of change does this PR introduce?

Chore - Renovate configuration only. No product code, no build files, no dependency versions change.

What is the new behavior?

Adds repo-specific grouping on top of the shared reactiveui/.github preset so related packages arrive as one reviewable PR:

• analyzers

• build tooling

• TUnit

• test tooling

• Verify.TUnit is compiled against a specific TUnit version, but the shared preset put TUnit in its own group and Verify.* in the .NET test stack - so a matched pair could land in two separate PRs and red the build. They are now grouped together.

What is the current behavior?

These packages are ungrouped, so each one opens its own PR even when it only makes sense to bump them together.

What might this PR break?

Nothing at build time - this file only affects how Renovate batches its own PRs. Any currently-open Renovate PR whose group name changes will be closed and reopened under the new branch name.

Checklist

• I have read the Contribute guide
• Tests have been added or updated (for bug fixes / features)
• Docs have been added or updated (for bug fixes / features)
• Changes target the main branch
• PR title follows Conventional Commits

Additional information

Validated with renovate-config-validator. Every pattern was checked against this repo's actual package list (no dead rules), and the merged preset+repo rule set was resolved through Renovate's applyPackageRules engine to confirm each package lands in the intended group.

[Copilot]

Pull request overview

This PR updates the repository’s Renovate configuration to add repo-specific dependency grouping rules on top of the shared reactiveui/.github preset, so Renovate opens fewer, more coherent update PRs (especially for coupled test dependencies like TUnit + Verify.TUnit).

Changes:

• Expanded extends into a multiline array (no functional change).
• Added packageRules to group related NuGet dependencies into four cohorts: analyzers, build tooling, TUnit (+ Verify.*), and test tooling.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.16%. Comparing base (6fd596d) to head (0f4075d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #471   +/-   ##
=======================================
  Coverage   62.16%   62.16%           
=======================================
  Files          75       75           
  Lines        4105     4105           
  Branches      572      572           
=======================================
  Hits         2552     2552           
  Misses       1385     1385           
  Partials      168      168           

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[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.