reasoning: admit verified user-supported unknowns without provenance edges

lib/graph/apply-proposal.js

@@ -75,12 +75,31 @@ function isCompoundQuestion(question) {
   return false;
 }
 
-function validateAddedUnknowns(graph, proposal) {
+function validateAddedUnknowns(graph, proposal, answerMeaning) {
   const errors = [];
   const addedUnknowns = proposal.addedNodes.filter(
     (node) => node.kind === "unknown",
   );
 
+  const userSupportedMeaningText = answerMeaning?.userSupportedMeaning;
+
+  function hasNodeLevelUserSupport(unknownNode) {
+    if (!userSupportedMeaningText) return false;
+
+    const unknownText = normaliseSemanticText(
+      [normaliseText(unknownNode.label), normaliseText(unknownNode.description)]
+        .filter(Boolean)
+        .join(" "),
+    );
+
+    const overlapRatio = semanticOverlapRatio(userSupportedMeaningText, unknownText);
+    const overlappingTokens = semanticContentTokens(userSupportedMeaningText).filter(
+      (token) => semanticContentTokens(unknownText).includes(token),
+    ).length;
+
+    return overlapRatio >= 0.4 || overlappingTokens >= 3;
+  }
+
   if (addedUnknowns.length > 3) {
     errors.push(
       `Proposal adds too many unknown nodes: ${addedUnknowns.length} (maximum 3)`,
@@ -180,7 +199,10 @@ function validateAddedUnknowns(graph, proposal) {
       );
     }
 
-    if (!hasExplicitAnswerDerivedRelationship(unknownNode)) {
+    if (
+      !hasNodeLevelUserSupport(unknownNode) &&
+      !hasExplicitAnswerDerivedRelationship(unknownNode)
+    ) {
       errors.push(
         `New unknown must be explicitly related to an answer-derived node: "${unknownNode.id}"`,
       );
@@ -3232,7 +3254,7 @@ export function applyValidatedProposal({
     ...validateSemanticDuplicateUnknowns(situationGraph, validatedProposal),
   );
   proposalCompatibilityErrors.push(
-    ...validateAddedUnknowns(situationGraph, validatedProposal),
+    ...validateAddedUnknowns(situationGraph, validatedProposal, validatedProposal.answerMeaning),
   );
 
   const selectedQuestionValidation = validateSelectedQuestion(