new advisories work and features gaps work

src/Scanner/__Libraries/StellaOps.Scanner.Reachability/RichGraph.cs

@@ -55,7 +55,9 @@ public sealed record RichGraphNode(
     IReadOnlyDictionary<string, string>? Attributes,
     string? SymbolDigest,
     ReachabilitySymbol? Symbol = null,
-    string? CodeBlockHash = null)
+    string? CodeBlockHash = null,
+    // Sprint: SPRINT_20260112_004_SCANNER_path_witness_nodehash (PW-SCN-002)
+    string? NodeHash = null)
 {
     public RichGraphNode Trimmed()
     {
@@ -71,6 +73,7 @@ public sealed record RichGraphNode(
             BuildId = string.IsNullOrWhiteSpace(BuildId) ? null : BuildId.Trim(),
             CodeBlockHash = string.IsNullOrWhiteSpace(CodeBlockHash) ? null : CodeBlockHash.Trim(),
             SymbolDigest = string.IsNullOrWhiteSpace(SymbolDigest) ? null : SymbolDigest.Trim(),
+            NodeHash = string.IsNullOrWhiteSpace(NodeHash) ? null : NodeHash.Trim(),
             Symbol = Symbol?.Trimmed(),
             Evidence = Evidence is null
                 ? Array.Empty<string>()

src/Scanner/__Libraries/StellaOps.Scanner.Reachability/Subgraph/ReachabilitySubgraphModels.cs

@@ -53,6 +53,14 @@ public sealed record ReachabilitySubgraphNode
 
     [JsonPropertyName("attributes")]
     public IReadOnlyDictionary<string, string>? Attributes { get; init; }
+
+    // Sprint: SPRINT_20260112_004_SCANNER_path_witness_nodehash (PW-SCN-002)
+
+    /// <summary>
+    /// Canonical node hash computed from PURL and symbol using NodeHashRecipe.
+    /// </summary>
+    [JsonPropertyName("nodeHash")]
+    public string? NodeHash { get; init; }
 }
 
 /// <summary>