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.

src/Signals/StellaOps.Signals/Persistence/IDeploymentRefsRepository.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -12,4 +13,52 @@ public interface IDeploymentRefsRepository
     /// Counts distinct deployments referencing a package.
     /// </summary>
     Task<int> CountDeploymentsAsync(string purl, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Gets deployment IDs referencing a package.
+    /// </summary>
+    Task<IReadOnlyList<string>> GetDeploymentIdsAsync(string purl, int limit, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Records or updates a deployment reference.
+    /// </summary>
+    Task UpsertAsync(DeploymentRef deployment, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Records multiple deployment references in a batch.
+    /// </summary>
+    Task BulkUpsertAsync(IEnumerable<DeploymentRef> deployments, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Gets deployment summary for a package.
+    /// </summary>
+    Task<DeploymentSummary?> GetSummaryAsync(string purl, CancellationToken cancellationToken = default);
+}
+
+/// <summary>
+/// Represents a deployment reference record.
+/// </summary>
+public sealed class DeploymentRef
+{
+    public required string Purl { get; init; }
+    public string? PurlVersion { get; init; }
+    public required string ImageId { get; init; }
+    public string? ImageDigest { get; init; }
+    public required string Environment { get; init; }
+    public string? Namespace { get; init; }
+    public string? Cluster { get; init; }
+    public string? Region { get; init; }
+}
+
+/// <summary>
+/// Summary of deployments for a package.
+/// </summary>
+public sealed class DeploymentSummary
+{
+    public required string Purl { get; init; }
+    public int ImageCount { get; init; }
+    public int EnvironmentCount { get; init; }
+    public int TotalDeployments { get; init; }
+    public DateTimeOffset? LastDeployment { get; init; }
+    public DateTimeOffset? FirstDeployment { get; init; }
 }

src/Signals/StellaOps.Signals/Persistence/IGraphMetricsRepository.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -15,11 +17,53 @@ public interface IGraphMetricsRepository
         string symbolId,
         string callgraphId,
         CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Stores computed metrics for a node.
+    /// </summary>
+    Task UpsertAsync(GraphMetrics metrics, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Bulk stores metrics for a call graph.
+    /// </summary>
+    Task BulkUpsertAsync(IEnumerable<GraphMetrics> metrics, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Gets callgraph IDs that need recomputation (older than threshold).
+    /// </summary>
+    Task<IReadOnlyList<string>> GetStaleCallgraphsAsync(
+        TimeSpan maxAge,
+        int limit,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Deletes all metrics for a callgraph.
+    /// </summary>
+    Task DeleteByCallgraphAsync(string callgraphId, CancellationToken cancellationToken = default);
 }
 
 /// <summary>
 /// Centrality metrics for a symbol.
 /// </summary>
-public sealed record GraphMetrics(
-    int Degree,
-    double Betweenness);
+public sealed class GraphMetrics
+{
+    public required string NodeId { get; init; }
+    public required string CallgraphId { get; init; }
+    public string NodeType { get; init; } = "symbol";
+
+    public int Degree { get; init; }
+    public int InDegree { get; init; }
+    public int OutDegree { get; init; }
+    public double Betweenness { get; init; }
+    public double? Closeness { get; init; }
+
+    public double? NormalizedBetweenness { get; init; }
+    public double? NormalizedDegree { get; init; }
+
+    public DateTimeOffset ComputedAt { get; init; }
+    public int? ComputationDurationMs { get; init; }
+    public string AlgorithmVersion { get; init; } = "1.0";
+
+    public int? TotalNodes { get; init; }
+    public int? TotalEdges { get; init; }
+}

src/Signals/StellaOps.Signals/Persistence/InMemoryDeploymentRefsRepository.cs

@@ -1,4 +1,7 @@
+using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -7,6 +10,7 @@ namespace StellaOps.Signals.Persistence;
 public sealed class InMemoryDeploymentRefsRepository : IDeploymentRefsRepository
 {
     private readonly ConcurrentDictionary<string, int> _deploymentsByPurl = new(StringComparer.OrdinalIgnoreCase);
+    private readonly ConcurrentDictionary<string, List<DeploymentRef>> _refsByPurl = new(StringComparer.OrdinalIgnoreCase);
 
     public void SetDeployments(string purl, int deployments)
     {
@@ -28,6 +32,82 @@ public sealed class InMemoryDeploymentRefsRepository : IDeploymentRefsRepository
             return Task.FromResult(0);
         }
 
-        return Task.FromResult(_deploymentsByPurl.TryGetValue(purl.Trim(), out var count) ? count : 0);
+        var key = purl.Trim();
+        if (_deploymentsByPurl.TryGetValue(key, out var count))
+            return Task.FromResult(count);
+
+        if (_refsByPurl.TryGetValue(key, out var refs))
+            return Task.FromResult(refs.Count);
+
+        return Task.FromResult(0);
+    }
+
+    public Task<IReadOnlyList<string>> GetDeploymentIdsAsync(string purl, int limit, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        if (string.IsNullOrWhiteSpace(purl))
+            return Task.FromResult<IReadOnlyList<string>>(Array.Empty<string>());
+
+        if (_refsByPurl.TryGetValue(purl.Trim(), out var refs))
+            return Task.FromResult<IReadOnlyList<string>>(refs.Take(limit).Select(r => r.ImageId).ToList());
+
+        return Task.FromResult<IReadOnlyList<string>>(Array.Empty<string>());
+    }
+
+    public Task UpsertAsync(DeploymentRef deployment, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        ArgumentNullException.ThrowIfNull(deployment);
+
+        var key = deployment.Purl.Trim();
+        _refsByPurl.AddOrUpdate(
+            key,
+            _ => new List<DeploymentRef> { deployment },
+            (_, list) =>
+            {
+                var existing = list.FindIndex(r =>
+                    r.ImageId == deployment.ImageId &&
+                    r.Environment == deployment.Environment);
+                if (existing >= 0)
+                    list[existing] = deployment;
+                else
+                    list.Add(deployment);
+                return list;
+            });
+
+        return Task.CompletedTask;
+    }
+
+    public Task BulkUpsertAsync(IEnumerable<DeploymentRef> deployments, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        ArgumentNullException.ThrowIfNull(deployments);
+
+        foreach (var deployment in deployments)
+        {
+            UpsertAsync(deployment, cancellationToken).GetAwaiter().GetResult();
+        }
+
+        return Task.CompletedTask;
+    }
+
+    public Task<DeploymentSummary?> GetSummaryAsync(string purl, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        if (string.IsNullOrWhiteSpace(purl))
+            return Task.FromResult<DeploymentSummary?>(null);
+
+        if (!_refsByPurl.TryGetValue(purl.Trim(), out var refs) || refs.Count == 0)
+            return Task.FromResult<DeploymentSummary?>(null);
+
+        return Task.FromResult<DeploymentSummary?>(new DeploymentSummary
+        {
+            Purl = purl,
+            ImageCount = refs.Select(r => r.ImageId).Distinct().Count(),
+            EnvironmentCount = refs.Select(r => r.Environment).Distinct().Count(),
+            TotalDeployments = refs.Count
+        });
     }
 }

src/Signals/StellaOps.Signals/Persistence/InMemoryGraphMetricsRepository.cs

@@ -1,4 +1,7 @@
+using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -30,6 +33,64 @@ public sealed class InMemoryGraphMetricsRepository : IGraphMetricsRepository
         return Task.FromResult(_metrics.TryGetValue(key, out var metrics) ? metrics : null);
     }
 
+    public Task UpsertAsync(GraphMetrics metrics, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        ArgumentNullException.ThrowIfNull(metrics);
+
+        var key = BuildKey(metrics.NodeId, metrics.CallgraphId);
+        _metrics[key] = metrics;
+        return Task.CompletedTask;
+    }
+
+    public Task BulkUpsertAsync(IEnumerable<GraphMetrics> metrics, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        ArgumentNullException.ThrowIfNull(metrics);
+
+        foreach (var m in metrics)
+        {
+            var key = BuildKey(m.NodeId, m.CallgraphId);
+            _metrics[key] = m;
+        }
+
+        return Task.CompletedTask;
+    }
+
+    public Task<IReadOnlyList<string>> GetStaleCallgraphsAsync(TimeSpan maxAge, int limit, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        var cutoff = DateTimeOffset.UtcNow - maxAge;
+        var staleGraphs = _metrics.Values
+            .Where(m => m.ComputedAt < cutoff)
+            .Select(m => m.CallgraphId)
+            .Distinct()
+            .Take(limit)
+            .ToList();
+
+        return Task.FromResult<IReadOnlyList<string>>(staleGraphs);
+    }
+
+    public Task DeleteByCallgraphAsync(string callgraphId, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        if (string.IsNullOrWhiteSpace(callgraphId))
+            return Task.CompletedTask;
+
+        var keysToRemove = _metrics.Keys
+            .Where(k => k.StartsWith(callgraphId.Trim() + "|", StringComparison.OrdinalIgnoreCase))
+            .ToList();
+
+        foreach (var key in keysToRemove)
+        {
+            _metrics.TryRemove(key, out _);
+        }
+
+        return Task.CompletedTask;
+    }
+
     private static string BuildKey(string symbolId, string callgraphId)
         => $"{callgraphId.Trim()}|{symbolId.Trim()}";
 }