Fix build and code structure improvements. New but essential UI functionality. CI improvements. Documentation improvements. AI module improvements.

src/Policy/StellaOps.Policy.Engine/ReachabilityFacts/IReachabilityFactsSignalsClient.cs

@@ -34,6 +34,138 @@ public interface IReachabilityFactsSignalsClient
     Task<bool> TriggerRecomputeAsync(
         SignalsRecomputeRequest request,
         CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Gets a reachability fact with its associated subgraph slice.
+    /// Fetches from Signals for the fact and ReachGraph Store for the subgraph.
+    /// </summary>
+    /// <param name="subjectKey">Subject key (scan ID or component key).</param>
+    /// <param name="cveId">Optional CVE ID to slice by.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>The reachability fact with subgraph, or null if not found.</returns>
+    Task<ReachabilityFactWithSubgraph?> GetWithSubgraphAsync(
+        string subjectKey,
+        string? cveId = null,
+        CancellationToken cancellationToken = default);
+}
+
+/// <summary>
+/// Response containing both the reachability fact and its subgraph slice.
+/// </summary>
+public sealed record ReachabilityFactWithSubgraph(
+    SignalsReachabilityFactResponse Fact,
+    ReachGraphSlice? Subgraph);
+
+/// <summary>
+/// Represents a slice of the reachability graph for a specific query.
+/// </summary>
+public sealed record ReachGraphSlice
+{
+    /// <summary>
+    /// Schema version.
+    /// </summary>
+    public string? SchemaVersion { get; init; }
+
+    /// <summary>
+    /// Slice query information.
+    /// </summary>
+    public ReachGraphSliceQuery? SliceQuery { get; init; }
+
+    /// <summary>
+    /// Parent graph digest.
+    /// </summary>
+    public string? ParentDigest { get; init; }
+
+    /// <summary>
+    /// BLAKE3 digest of this slice.
+    /// </summary>
+    public string? Digest { get; init; }
+
+    /// <summary>
+    /// Nodes in the slice.
+    /// </summary>
+    public List<ReachGraphSliceNode>? Nodes { get; init; }
+
+    /// <summary>
+    /// Edges in the slice.
+    /// </summary>
+    public List<ReachGraphSliceEdge>? Edges { get; init; }
+
+    /// <summary>
+    /// Number of nodes.
+    /// </summary>
+    public int NodeCount { get; init; }
+
+    /// <summary>
+    /// Number of edges.
+    /// </summary>
+    public int EdgeCount { get; init; }
+
+    /// <summary>
+    /// Sink node IDs.
+    /// </summary>
+    public List<string>? Sinks { get; init; }
+
+    /// <summary>
+    /// Paths from entrypoints to sinks.
+    /// </summary>
+    public List<ReachGraphPath>? Paths { get; init; }
+}
+
+/// <summary>
+/// Slice query information.
+/// </summary>
+public sealed record ReachGraphSliceQuery
+{
+    public string? Type { get; init; }
+    public string? Query { get; init; }
+    public string? Cve { get; init; }
+}
+
+/// <summary>
+/// Node in a reachability graph slice.
+/// </summary>
+public sealed record ReachGraphSliceNode
+{
+    public string? Id { get; init; }
+    public string? Kind { get; init; }
+    public string? Ref { get; init; }
+    public string? File { get; init; }
+    public int? Line { get; init; }
+    public bool IsEntrypoint { get; init; }
+    public bool IsSink { get; init; }
+}
+
+/// <summary>
+/// Edge in a reachability graph slice.
+/// </summary>
+public sealed record ReachGraphSliceEdge
+{
+    public string? From { get; init; }
+    public string? To { get; init; }
+    public ReachGraphEdgeExplanation? Why { get; init; }
+}
+
+/// <summary>
+/// Edge explanation in a reachability graph.
+/// </summary>
+public sealed record ReachGraphEdgeExplanation
+{
+    public string? Type { get; init; }
+    public string? Loc { get; init; }
+    public string? Guard { get; init; }
+    public double Confidence { get; init; }
+}
+
+/// <summary>
+/// Path from entrypoint to sink.
+/// </summary>
+public sealed record ReachGraphPath
+{
+    public string? Entrypoint { get; init; }
+    public string? Sink { get; init; }
+    public List<string>? Hops { get; init; }
+    public List<ReachGraphSliceEdge>? Edges { get; init; }
 }
 
 /// <summary>