feat(confidence-engine): reopen clarified questions

lib/graph/reopen-resolved-unknown.js

@@ -0,0 +1,35 @@
+/**
+ * Deterministically reopen a resolved unknown node in a SituationGraph.
+ *
+ * Transition: node.status "resolved" → "unknown", and removes the node's ID
+ * from resolvedNodeIds. This reverses canonical resolution so the question
+ * reappears among Open Questions for further investigation.
+ *
+ * Idempotent — if the target is not a currently-resolved unknown, returns the
+ * original graph unchanged (no mutation). Does NOT create nodes, delete edges,
+ * or touch contributions/findings/historical evidence.
+ */
+
+export function reopenResolvedUnknown(situationGraph, nodeId) {
+  if (!situationGraph || !nodeId) return situationGraph;
+
+  const nodeIndex = situationGraph.nodes.findIndex((n) => n.id === nodeId);
+  if (nodeIndex === -1) return situationGraph;
+
+  const node = situationGraph.nodes[nodeIndex];
+  if (node.kind !== "unknown" || node.status !== "resolved") return situationGraph;
+
+  const newNode = { ...node, status: "unknown" };
+  const newNodes = [...situationGraph.nodes];
+  newNodes[nodeIndex] = newNode;
+
+  const newResolvedNodeIds = [
+    ...(situationGraph.resolvedNodeIds || []),
+  ].filter((id) => id !== nodeId);
+
+  return {
+    ...situationGraph,
+    nodes: newNodes,
+    resolvedNodeIds: newResolvedNodeIds,
+  };
+}