Add call graph fixtures for various languages and scenarios

- Introduced `all-edge-reasons.json` to test edge resolution reasons in .NET.
- Added `all-visibility-levels.json` to validate method visibility levels in .NET.
- Created `dotnet-aspnetcore-minimal.json` for a minimal ASP.NET Core application.
- Included `go-gin-api.json` for a Go Gin API application structure.
- Added `java-spring-boot.json` for the Spring PetClinic application in Java.
- Introduced `legacy-no-schema.json` for legacy application structure without schema.
- Created `node-express-api.json` for an Express.js API application structure.

tests/reachability/StellaOps.Signals.Reachability.Tests/ReachabilityScoringTests.cs

@@ -251,6 +251,21 @@ public sealed class ReachabilityScoringTests
             storage[document.SubjectKey] = document;
             return Task.FromResult(document);
         }
+
+        public Task<IReadOnlyList<ReachabilityFactDocument>> GetExpiredAsync(DateTimeOffset olderThan, int limit, CancellationToken cancellationToken) =>
+            Task.FromResult<IReadOnlyList<ReachabilityFactDocument>>(Array.Empty<ReachabilityFactDocument>());
+
+        public Task<bool> DeleteAsync(string subjectKey, CancellationToken cancellationToken)
+        {
+            var removed = storage.Remove(subjectKey);
+            return Task.FromResult(removed);
+        }
+
+        public Task<int> GetRuntimeFactsCountAsync(string subjectKey, CancellationToken cancellationToken) =>
+            Task.FromResult(0);
+
+        public Task TrimRuntimeFactsAsync(string subjectKey, int maxCount, CancellationToken cancellationToken) =>
+            Task.CompletedTask;
     }
 
     private sealed class InMemoryReachabilityCache : IReachabilityCache
@@ -286,6 +301,21 @@ public sealed class ReachabilityScoringTests
 
         public Task<int> CountBySubjectAsync(string subjectKey, CancellationToken cancellationToken) =>
             Task.FromResult(0);
+
+        public Task BulkUpdateAsync(IEnumerable<UnknownSymbolDocument> unknowns, CancellationToken cancellationToken) =>
+            Task.CompletedTask;
+
+        public Task<IReadOnlyList<string>> GetAllSubjectKeysAsync(CancellationToken cancellationToken) =>
+            Task.FromResult((IReadOnlyList<string>)Array.Empty<string>());
+
+        public Task<IReadOnlyList<UnknownSymbolDocument>> GetDueForRescanAsync(UnknownsBand band, int limit, CancellationToken cancellationToken) =>
+            Task.FromResult((IReadOnlyList<UnknownSymbolDocument>)Array.Empty<UnknownSymbolDocument>());
+
+        public Task<IReadOnlyList<UnknownSymbolDocument>> QueryAsync(UnknownsBand? band, int limit, int offset, CancellationToken cancellationToken) =>
+            Task.FromResult((IReadOnlyList<UnknownSymbolDocument>)Array.Empty<UnknownSymbolDocument>());
+
+        public Task<UnknownSymbolDocument?> GetByIdAsync(string id, CancellationToken cancellationToken) =>
+            Task.FromResult<UnknownSymbolDocument?>(null);
     }
 
     private sealed class NullEventsPublisher : IEventsPublisher