test(ui): explore branch as workspace context

components/scenario-form.jsx

@@ -543,24 +543,30 @@ export default function ScenarioForm() {
           <div className="grid grid-cols-1 gap-6 lg:grid-cols-4">
             {/* Workspace (3/4) */}
             <div className="lg:col-span-3">
-              <ReasoningWorkspace
-                scenario={scenario}
-                status={status}
-                updateStatus={updateStatus}
-                currentUnderstanding={currentUnderstanding}
-                result={{
-                  ...(result || {}),
-                  situationGraph: updateResult?.updatedSituationGraph ?? result?.situationGraph,
-                  selectedQuestion: updateResult?.selectedQuestion ?? result?.selectedQuestion,
-                  newlySurfacedNodeIds: result?.newlySurfacedNodeIds || [],
-                  diagnostics: result?.diagnostics || null,
-                  updateError,
-                }}
-                answer={answer}
-                setAnswer={setAnswer}
-                onAnswerSubmit={handleUpdate}
-                lastSubmittedAnswer={lastSubmittedAnswer}
-                onRestart={() => {
+              {/* Build branch context for the active branch */}
+              {(() => {
+                const activeBranch = BRANCHES.find(b => b.id === activeBranchId);
+                const branchContext = activeBranch ? { label: activeBranch.label, origin: activeBranch.origin } : null;
+                return (
+                  <ReasoningWorkspace
+                    scenario={scenario}
+                    status={status}
+                    updateStatus={updateStatus}
+                    currentUnderstanding={currentUnderstanding}
+                    result={{
+                      ...(result || {}),
+                      situationGraph: updateResult?.updatedSituationGraph ?? result?.situationGraph,
+                      selectedQuestion: updateResult?.selectedQuestion ?? result?.selectedQuestion,
+                      newlySurfacedNodeIds: result?.newlySurfacedNodeIds || [],
+                      diagnostics: result?.diagnostics || null,
+                      updateError,
+                    }}
+                    answer={answer}
+                    setAnswer={setAnswer}
+                    onAnswerSubmit={handleUpdate}
+                    lastSubmittedAnswer={lastSubmittedAnswer}
+                    branchContext={branchContext}
+                    onRestart={() => {
                   clearSession();
                   setStatus("idle");
                   setResult(null);
@@ -572,7 +578,9 @@ export default function ScenarioForm() {
                   setUpdateError(null);
                 }}
               />
-            </div>
+            );
+          })()}
+        </div>
 
             {/* Branch switcher (1/4 sidebar) */}
             <div className="lg:col-span-1">