Add JB perf testing project.

[adamhathcock]

Got some memory allocation wins with RAR
Pooling for LZMA reading

Testing for more low hanging fruit...

[Copilot]

Pull Request Overview

This PR adds a new performance testing project to help identify and address memory allocation bottlenecks in SharpCompress. The primary focus is on optimizing RAR decompression through ArrayPool usage and other performance improvements.

Key changes:

• Added new SharpCompress.Performance project with JetBrains profiler integration for CPU and memory analysis
• Implemented ArrayPool-based memory pooling for BitInput and RarVM to reduce allocations
• Optimized RAR unpacking algorithms and LZMA decompression with better resource disposal
• Simplified unsigned right shift operations and improved array operations efficiency

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
tests/SharpCompress.Performance/*	New performance testing project with profiling infrastructure
src/SharpCompress/Utility.cs	Simplified unsigned right shift implementations
src/SharpCompress/NotNullExtensions.cs	Added aggressive inlining to NotNullOrEmpty method
src/SharpCompress/Compressors/Rar/VM/RarVM.cs	Converted to use ArrayPool for memory allocation and improved array operations
src/SharpCompress/Compressors/Rar/VM/BitInput.cs	Added IDisposable with ArrayPool-based buffer management
src/SharpCompress/Compressors/Rar/UnpackV1/*	Optimized decoding algorithms and cleanup, added proper disposal
src/SharpCompress/Compressors/LZMA/*	Added proper disposal of OutWindow resources

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[Copilot]

Pull Request Overview

Copilot reviewed 18 out of 18 changed files in this pull request and generated 4 comments.

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