Add unit tests and implementations for MongoDB index models and OpenAPI metadata

- Implemented `MongoIndexModelTests` to verify index models for various stores.
- Created `OpenApiMetadataFactory` with methods to generate OpenAPI metadata.
- Added tests for `OpenApiMetadataFactory` to ensure expected defaults and URL overrides.
- Introduced `ObserverSurfaceSecrets` and `WebhookSurfaceSecrets` for managing secrets.
- Developed `RuntimeSurfaceFsClient` and `WebhookSurfaceFsClient` for manifest retrieval.
- Added dependency injection tests for `SurfaceEnvironmentRegistration` in both Observer and Webhook contexts.
- Implemented tests for secret resolution in `ObserverSurfaceSecretsTests` and `WebhookSurfaceSecretsTests`.
- Created `EnsureLinkNotMergeCollectionsMigrationTests` to validate MongoDB migration logic.
- Added project files for MongoDB tests and NuGet package mirroring.

src/Scanner/__Tests/StellaOps.Scanner.Analyzers.Lang.Tests/DotNet/DotNetEntrypointResolverTests.cs

@@ -0,0 +1,51 @@
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using StellaOps.Scanner.Analyzers.Lang;
+using StellaOps.Scanner.Analyzers.Lang.DotNet.Internal;
+using StellaOps.Scanner.Analyzers.Lang.Tests.TestUtilities;
+
+namespace StellaOps.Scanner.Analyzers.Lang.Tests.DotNet;
+
+public sealed class DotNetEntrypointResolverTests
+{
+    [Fact]
+    public async Task SimpleFixtureResolvesSingleEntrypointAsync()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var fixturePath = TestPaths.ResolveFixture("lang", "dotnet", "simple");
+
+        var context = new LanguageAnalyzerContext(fixturePath, TimeProvider.System);
+        var entrypoints = await DotNetEntrypointResolver.ResolveAsync(context, cancellationToken);
+
+        Assert.Single(entrypoints);
+
+        var entrypoint = entrypoints[0];
+        Assert.Equal("Sample.App", entrypoint.Name);
+        Assert.Equal("Sample.App:Microsoft.AspNetCore.App@10.0.0+Microsoft.NETCore.App@10.0.0+net10.0:any+linux+linux-x64+unix+win+win-x86:frameworkdependent", entrypoint.Id);
+        Assert.Contains("net10.0", entrypoint.TargetFrameworks);
+        Assert.Contains("linux-x64", entrypoint.RuntimeIdentifiers);
+        Assert.Equal("Sample.App.deps.json", entrypoint.RelativeDepsPath);
+        Assert.Equal("Sample.App.runtimeconfig.json", entrypoint.RelativeRuntimeConfigPath);
+        Assert.Equal(DotNetPublishKind.FrameworkDependent, entrypoint.PublishKind);
+    }
+
+    [Fact]
+    public async Task DeterministicOrderingIsStableAsync()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var fixturePath = TestPaths.ResolveFixture("lang", "dotnet", "multi");
+
+        var context = new LanguageAnalyzerContext(fixturePath, TimeProvider.System);
+        var first = await DotNetEntrypointResolver.ResolveAsync(context, cancellationToken);
+        var second = await DotNetEntrypointResolver.ResolveAsync(context, cancellationToken);
+
+        Assert.Equal(first.Count, second.Count);
+        for (var i = 0; i < first.Count; i++)
+        {
+            Assert.Equal(first[i].Id, second[i].Id);
+            Assert.True(first[i].TargetFrameworks.SequenceEqual(second[i].TargetFrameworks));
+            Assert.True(first[i].RuntimeIdentifiers.SequenceEqual(second[i].RuntimeIdentifiers));
+        }
+    }
+}