PerfDiff: Address static analysis warnings and code standards violations

[coderabbitai]

Description

Multiple static analysis warnings and code standards violations identified across PerfDiff files that need to be addressed.

Issues Identified from PR #565

Assembly Version Attributes Missing

• Multiple files missing AssemblyVersion attribute warnings
• Affects: All new DataContracts, Regression strategies, and core classes

Magic Numbers

• 1000000 hardcoded in PercentileRegressionStrategy.cs:21 (nanoseconds to milliseconds conversion)
• 0.1 hardcoded in RegressionStrategyHelper.cs:71

Collection Abstraction Issues

• Statistics.cs: Lines 61, 66, 71 use concrete IList<double> instead of abstractions
• Meziantou analyzer rule MA0016 violations

API Naming Issues

• Methods with Async suffix that don't follow conventions:
  • BenchmarkComparisonService.CompareAsync
  • PerfDiff.CompareAsync
  • BenchmarkDotNetDiffer.TryCompareBenchmarkDotNetResultsAsync

Affected Files

• src/tools/PerfDiff/BDN/DataContracts/Statistics.cs
• src/tools/PerfDiff/BDN/Regression/PercentileRegressionStrategy.cs
• src/tools/PerfDiff/BDN/Regression/RegressionStrategyHelper.cs
• src/tools/PerfDiff/BDN/BenchmarkComparisonService.cs
• src/tools/PerfDiff/PerfDiff.cs
• Multiple DataContract files

Suggested Solutions

• Add AssemblyInfo.cs with proper version attributes
• Extract magic numbers to named constants
• Use appropriate collection abstractions (IReadOnlyList, ICollection)
• Review and fix async method naming conventions

Reference

• Original PR: feat: modularize PerfDiff regression detection, update analyzer reporting, and clarify CI performance documentation #565
• Static analysis reports: Codacy, GitHub Checks, Meziantou Analyzer