Add rank feedback handoff contract

server.js

@@ -571,6 +571,39 @@ function createDecisionBrief({ idea, context, mode, ranked, provenance }) {
   };
 }
 
+function createHandoffContract({ ranked, provenance }) {
+  const warnings = [];
+  if (!provenance?.artifactId) warnings.push('missing source artifact id');
+  if (!provenance?.originalPrompt) warnings.push('missing original prompt provenance');
+
+  const itemTrace = ranked.map(item => {
+    if (!item.provenance?.sourceSection) warnings.push(`missing source section for ${item.id}`);
+    if (!item.factors?.evidenceNeeded && ['do', 'test'].includes(item.lane?.id)) warnings.push(`missing evidence needed for active item ${item.id}`);
+    return {
+      id: item.id,
+      title: item.title,
+      lane: item.lane?.id || 'defer',
+      sourceSection: item.provenance?.sourceSection || '',
+      sourceId: item.provenance?.sourceId || '',
+      evidenceNeeded: item.factors?.evidenceNeeded || '',
+    };
+  });
+
+  return {
+    schema: 'rank-feedback-result-v1',
+    source: {
+      schema: provenance?.schema || '',
+      source: provenance?.source || '',
+      artifactId: provenance?.artifactId || '',
+      snapshotTitle: provenance?.snapshotTitle || '',
+      conceptMapId: provenance?.conceptMapId || '',
+      hasOriginalPrompt: Boolean(provenance?.originalPrompt),
+    },
+    itemTrace,
+    warnings: [...new Set(warnings)],
+  };
+}
+
 app.post('/api/rank-feedback', (req, res) => {
   const idea = cleanMultiline(req.body?.idea || '', 3000);
   const context = cleanMultiline(req.body?.context || '', 3000);
@@ -591,12 +624,15 @@ app.post('/api/rank-feedback', (req, res) => {
         concern: concernFor(rankedOption),
       };
     });
+  const brief = createDecisionBrief({ idea, context, mode, ranked: options, provenance });
+  const handoff = createHandoffContract({ ranked: options, provenance });
   res.json({
     ok: true,
     mode: { id: modeId in judgementModes ? modeId : 'progress', label: mode.label },
     input: { idea, context, optionCount: options.length, provenance },
     ranked: options,
-    brief: createDecisionBrief({ idea, context, mode, ranked: options, provenance }),
+    brief,
+    handoff,
     buildOrder: {
       doFirst: options.filter(item => item.lane.id === 'do').map(item => item.id),
       validateNext: options.filter(item => item.lane.id === 'test').map(item => item.id),