Add unit tests for RancherHubConnector and various exporters

- Implemented tests for RancherHubConnector to validate fetching documents, handling errors, and managing state.
- Added tests for CsafExporter to ensure deterministic serialization of CSAF documents.
- Created tests for CycloneDX exporters and reconciler to verify correct handling of VEX claims and output structure.
- Developed OpenVEX exporter tests to confirm the generation of canonical OpenVEX documents and statement merging logic.
- Introduced Rust file caching and license scanning functionality, including a cache key structure and hash computation.
- Added sample Cargo.toml and LICENSE files for testing Rust license scanning functionality.

src/Scanner/__Tests/StellaOps.Scanner.Analyzers.Lang.Tests/Rust/RustLanguageAnalyzerTests.cs

@@ -1,4 +1,6 @@
+using System;
 using System.IO;
+using System.Linq;
 using StellaOps.Scanner.Analyzers.Lang.Rust;
 using StellaOps.Scanner.Analyzers.Lang.Tests.Harness;
 using StellaOps.Scanner.Analyzers.Lang.Tests.TestUtilities;
@@ -31,4 +33,27 @@ public sealed class RustLanguageAnalyzerTests
             cancellationToken,
             usageHints);
     }
+
+    [Fact]
+    public async Task AnalyzerIsThreadSafeUnderConcurrencyAsync()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var fixturePath = TestPaths.ResolveFixture("lang", "rust", "simple");
+
+        var analyzers = new ILanguageAnalyzer[]
+        {
+            new RustLanguageAnalyzer()
+        };
+
+        var workers = Math.Max(Environment.ProcessorCount, 4);
+        var tasks = Enumerable.Range(0, workers)
+            .Select(_ => LanguageAnalyzerTestHarness.RunToJsonAsync(fixturePath, analyzers, cancellationToken));
+
+        var results = await Task.WhenAll(tasks);
+        var baseline = results[0];
+        foreach (var result in results)
+        {
+            Assert.Equal(baseline, result);
+        }
+    }
 }