fix: link emergent unknowns to answer-derived graph nodes

tests/ui/scenario-form.test.jsx

@@ -438,6 +438,26 @@ describe("graph-backed UI rendering", () => {
     expect(html).toContain("Commercial value definition");
   });
 
+  it("successful update renders prior and new state together", () => {
+    const html = renderToStaticMarkup(
+      <GraphUpdateView
+        updateResult={{
+          ...makeUpdateSuccess(),
+          previousSituationGraph: makeGraphResult().situationGraph,
+        }}
+      />,
+    );
+
+    expect(html).toContain("Previous active unknown");
+    expect(html).toContain("Resolved unknowns");
+    expect(html).toContain("Newly surfaced unknowns");
+    expect(html).toContain("New active unknown");
+    expect(html).toContain("Next question");
+    expect(html).toContain(
+      "How should commercial value be defined for this decision?",
+    );
+  });
+
   it("situation graph marks newly surfaced and active unknowns", () => {
     const html = renderToStaticMarkup(
       <SituationGraphView
@@ -514,6 +534,30 @@ describe("graph-backed UI rendering", () => {
     expect(html).toContain("bad proposal");
   });
 
+  it("failed update does not fabricate history", () => {
+    const html = renderToStaticMarkup(
+      <>
+        <UpdateErrorPanel
+          updateError={{
+            error: "Update case failed",
+            errors: [
+              'New unknown must be explicitly related to an answer-derived node: "nu_commercial_val"',
+            ],
+          }}
+        />
+        <GraphUpdateView updateResult={null} />
+      </>,
+    );
+
+    expect(html).toContain("Update error: Update case failed");
+    expect(html).toContain("nu_commercial_val");
+    expect(html).not.toContain("Previous active unknown");
+    expect(html).not.toContain("Resolved unknowns");
+    expect(html).not.toContain("Newly surfaced unknowns");
+    expect(html).not.toContain("New active unknown");
+    expect(html).not.toContain("Proposal details");
+  });
+
   it("proposal details remain collapsible", () => {
     const html = renderToStaticMarkup(
       <GraphUpdateView updateResult={makeUpdateSuccess()} />,