Resolve ReSharper 2025.2 warnings

[vbaderks]

No description provided.

[Copilot]

Pull Request Overview

This PR resolves ReSharper 2025.2 warnings by addressing code analysis suggestions and updating package versions.

• Simplifies parentheses usage in expressions to reduce redundancy
• Changes default! to null! for nullable reference type suppression consistency
• Makes local functions static where possible to improve performance
• Updates xunit packages to latest versions

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/TraitsTest.cs	Simplifies parentheses in assertion expression
samples/Convert/Program.cs	Makes local functions static and removes unused using
benchmark/Micro/GenericColorTransformation.cs	Updates null suppressors and simplifies expressions
benchmark/Micro/ComputeReconstructedSample.cs	Changes default! to null! for consistency
benchmark/Micro/BlockCopy.cs	Changes default! to null! for consistency
benchmark/Micro/Abs.cs	Updates null suppressors and uses pattern matching
Directory.Packages.props	Updates xunit package versions
CharLSDotNet.sln.DotSettings	Adds ReSharper inspection configuration
.globalconfig	Adds IDE diagnostic suppressions
.editorconfig	Adds code style preferences and ReSharper settings

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[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
CharLS.Managed	96%	92%	1804	✔
CharLS.Managed	96%	92%	1804	✔
Summary	96% (6700 / 6986)	92% (2736 / 2986)	3608	✔