feat: Add RustFS artifact object store and migration tool

- Implemented RustFsArtifactObjectStore for managing artifacts in RustFS.
- Added unit tests for RustFsArtifactObjectStore functionality.
- Created a RustFS migrator tool to transfer objects from S3 to RustFS.
- Introduced policy preview and report models for API integration.
- Added fixtures and tests for policy preview and report functionality.
- Included necessary metadata and scripts for cache_pkg package.

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers.Tests/BaselineLoaderTests.cs

@@ -0,0 +1,37 @@
+using System.Text;
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+using Xunit;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Tests;
+
+public sealed class BaselineLoaderTests
+{
+    [Fact]
+    public async Task LoadAsync_ReadsCsvIntoDictionary()
+    {
+        var csv = """
+            scenario,iterations,sample_count,mean_ms,p95_ms,max_ms
+            node_monorepo_walk,5,4,9.4303,36.1354,45.0012
+            python_site_packages_walk,5,10,12.1000,18.2000,26.3000
+            """;
+
+        var path = await WriteTempFileAsync(csv);
+
+        var result = await BaselineLoader.LoadAsync(path, CancellationToken.None);
+
+        Assert.Equal(2, result.Count);
+        var entry = Assert.Contains("node_monorepo_walk", result);
+        Assert.Equal(5, entry.Iterations);
+        Assert.Equal(4, entry.SampleCount);
+        Assert.Equal(9.4303, entry.MeanMs, 4);
+        Assert.Equal(36.1354, entry.P95Ms, 4);
+        Assert.Equal(45.0012, entry.MaxMs, 4);
+    }
+
+    private static async Task<string> WriteTempFileAsync(string content)
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"baseline-{Guid.NewGuid():N}.csv");
+        await File.WriteAllTextAsync(path, content, Encoding.UTF8);
+        return path;
+    }
+}

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers.Tests/BenchmarkJsonWriterTests.cs

@@ -0,0 +1,41 @@
+using System.Text.Json;
+using StellaOps.Bench.ScannerAnalyzers;
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+using StellaOps.Bench.ScannerAnalyzers.Reporting;
+using Xunit;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Tests;
+
+public sealed class BenchmarkJsonWriterTests
+{
+    [Fact]
+    public async Task WriteAsync_EmitsMetadataAndScenarioDetails()
+    {
+        var metadata = new BenchmarkJsonMetadata("1.0", DateTimeOffset.Parse("2025-10-23T12:00:00Z"), "abc123", "ci");
+        var result = new ScenarioResult(
+            "scenario",
+            "Scenario",
+            SampleCount: 5,
+            MeanMs: 10,
+            P95Ms: 12,
+            MaxMs: 20,
+            Iterations: 5,
+            ThresholdMs: 5000);
+        var baseline = new BaselineEntry("scenario", 5, 5, 9, 11, 10);
+        var report = new BenchmarkScenarioReport(result, baseline, 1.2);
+
+        var path = Path.Combine(Path.GetTempPath(), $"bench-{Guid.NewGuid():N}.json");
+        await BenchmarkJsonWriter.WriteAsync(path, metadata, new[] { report }, CancellationToken.None);
+
+        using var document = JsonDocument.Parse(await File.ReadAllTextAsync(path));
+        var root = document.RootElement;
+
+        Assert.Equal("1.0", root.GetProperty("schemaVersion").GetString());
+        Assert.Equal("abc123", root.GetProperty("commit").GetString());
+        var scenario = root.GetProperty("scenarios")[0];
+        Assert.Equal("scenario", scenario.GetProperty("id").GetString());
+        Assert.Equal(20, scenario.GetProperty("maxMs").GetDouble());
+        Assert.Equal(10, scenario.GetProperty("baseline").GetProperty("maxMs").GetDouble());
+        Assert.True(scenario.GetProperty("regression").GetProperty("breached").GetBoolean());
+    }
+}

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers.Tests/BenchmarkScenarioReportTests.cs

@@ -0,0 +1,58 @@
+using StellaOps.Bench.ScannerAnalyzers;
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+using StellaOps.Bench.ScannerAnalyzers.Reporting;
+using Xunit;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Tests;
+
+public sealed class BenchmarkScenarioReportTests
+{
+    [Fact]
+    public void RegressionRatio_ComputedWhenBaselinePresent()
+    {
+        var result = new ScenarioResult(
+            "scenario",
+            "Scenario",
+            SampleCount: 5,
+            MeanMs: 10,
+            P95Ms: 12,
+            MaxMs: 20,
+            Iterations: 5,
+            ThresholdMs: 5000);
+
+        var baseline = new BaselineEntry(
+            "scenario",
+            Iterations: 5,
+            SampleCount: 5,
+            MeanMs: 8,
+            P95Ms: 11,
+            MaxMs: 15);
+
+        var report = new BenchmarkScenarioReport(result, baseline, regressionLimit: 1.2);
+
+        Assert.True(report.MaxRegressionRatio.HasValue);
+        Assert.Equal(20d / 15d, report.MaxRegressionRatio.Value, 6);
+        Assert.True(report.RegressionBreached);
+        Assert.Contains("+33.3%", report.BuildRegressionFailureMessage());
+    }
+
+    [Fact]
+    public void RegressionRatio_NullWhenBaselineMissing()
+    {
+        var result = new ScenarioResult(
+            "scenario",
+            "Scenario",
+            SampleCount: 5,
+            MeanMs: 10,
+            P95Ms: 12,
+            MaxMs: 20,
+            Iterations: 5,
+            ThresholdMs: 5000);
+
+        var report = new BenchmarkScenarioReport(result, baseline: null, regressionLimit: 1.2);
+
+        Assert.Null(report.MaxRegressionRatio);
+        Assert.False(report.RegressionBreached);
+        Assert.Null(report.BuildRegressionFailureMessage());
+    }
+}

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers.Tests/PrometheusWriterTests.cs

@@ -0,0 +1,32 @@
+using StellaOps.Bench.ScannerAnalyzers;
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+using StellaOps.Bench.ScannerAnalyzers.Reporting;
+using Xunit;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Tests;
+
+public sealed class PrometheusWriterTests
+{
+    [Fact]
+    public void Write_EmitsMetricsForScenario()
+    {
+        var result = new ScenarioResult(
+            "scenario_a",
+            "Scenario A",
+            SampleCount: 5,
+            MeanMs: 10,
+            P95Ms: 12,
+            MaxMs: 20,
+            Iterations: 5,
+            ThresholdMs: 5000);
+        var baseline = new BaselineEntry("scenario_a", 5, 5, 9, 11, 18);
+        var report = new BenchmarkScenarioReport(result, baseline, 1.2);
+
+        var path = Path.Combine(Path.GetTempPath(), $"metrics-{Guid.NewGuid():N}.prom");
+        PrometheusWriter.Write(path, new[] { report });
+
+        var contents = File.ReadAllText(path);
+        Assert.Contains("scanner_analyzer_bench_max_ms{scenario=\"scenario_a\"} 20", contents);
+        Assert.Contains("scanner_analyzer_bench_regression_ratio{scenario=\"scenario_a\"}", contents);
+    }
+}

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers.Tests/StellaOps.Bench.ScannerAnalyzers.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <LangVersion>preview</LangVersion>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.0" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="coverlet.collector" Version="6.0.4">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\StellaOps.Bench.ScannerAnalyzers\StellaOps.Bench.ScannerAnalyzers.csproj" />
+  </ItemGroup>
+</Project>