fix: handle unjustified unknown selection ties

lib/graph/apply-proposal.js

@@ -1,5 +1,8 @@
 import { describeGraph } from "./builder.js";
-import { formulateQuestion } from "./question-formulator.js";
+import {
+  formulateQuestion,
+  formulateTieResolutionQuestion,
+} from "./question-formulator.js";
 import { graphUpdateSchema, situationGraphSchema } from "./schema.js";
 import {
   applyGraphUpdate,
@@ -623,18 +626,25 @@ export function applyValidatedProposal({ situationGraph, proposal }) {
     updatedSituationGraph.resolvedNodeIds,
   );
 
-  if (deterministicSelection?.nodeId) {
+  if (
+    deterministicSelection?.status === "selected" &&
+    deterministicSelection?.nodeId
+  ) {
     newActiveUnknownNodeId = deterministicSelection.nodeId;
+  } else if (deterministicSelection?.status === "ambiguous") {
+    newActiveUnknownNodeId = null;
   }
 
   updatedSituationGraph.activeUnknownNodeId = newActiveUnknownNodeId;
   updatedSituationGraph.currentSummary = describeGraph(updatedSituationGraph);
 
-  const selectedNode = deterministicSelection?.nodeId
-    ? updatedSituationGraph.nodes.find(
-        (node) => node.id === deterministicSelection.nodeId,
-      )
-    : null;
+  const selectedNode =
+    deterministicSelection?.status === "selected" &&
+    deterministicSelection?.nodeId
+      ? updatedSituationGraph.nodes.find(
+          (node) => node.id === deterministicSelection.nodeId,
+        )
+      : null;
   const formulatedQuestion = selectedNode
     ? formulateQuestion({
         node: selectedNode,
@@ -645,20 +655,28 @@ export function applyValidatedProposal({ situationGraph, proposal }) {
             .filter(
               (value) => typeof value === "string" && value.trim().length > 0,
             ),
+          selectionState: deterministicSelection,
         },
       })
     : null;
 
-  const finalSelectedQuestion = deterministicSelection
-    ? {
-        nodeId: deterministicSelection.nodeId,
-        question:
-          formulatedQuestion?.question || deterministicSelection.question,
-        reason: formulatedQuestion?.reason || deterministicSelection.reason,
-        strategy: formulatedQuestion?.strategy,
-        investigationStrategy: formulatedQuestion?.investigationStrategy,
-      }
-    : null;
+  const finalSelectedQuestion =
+    deterministicSelection?.status === "ambiguous"
+      ? {
+          nodeId: null,
+          tiedCandidateIds: deterministicSelection.tiedCandidateIds,
+          ...formulateTieResolutionQuestion({ graph: updatedSituationGraph }),
+        }
+      : deterministicSelection?.status === "selected"
+        ? {
+            nodeId: deterministicSelection.nodeId,
+            question:
+              formulatedQuestion?.question || deterministicSelection.question,
+            reason: formulatedQuestion?.reason || deterministicSelection.reason,
+            strategy: formulatedQuestion?.strategy,
+            investigationStrategy: formulatedQuestion?.investigationStrategy,
+          }
+        : null;
 
   const resultGraphValidation = situationGraphSchema.safeParse(
     updatedSituationGraph,