test(ui): isolate branch scoped workspace experiment

components/scenario-form.jsx

@@ -6,6 +6,7 @@ import DiagnosticsView from "@/components/diagnostics-view";
 import ReasoningWorkspace, { LoadingOverlay, ContinueLaterBanner } from "@/components/reasoning-workspace";
 import ExperimentalBranchSwitcher, { PulseStyle } from "@/components/experimental/branch-switcher";
 import { mockFetch, AVAILABLE_SCENARIOS } from "@/lib/mocks/confidence-engine/mock-client";
+import { useBranchScopedFixture } from "@/lib/fixtures/rto26b-branch-scoped.mjs";
 
 /* Compile-time env resolution — NEXT_PUBLIC_ vars are injected by Next.js at build */
 const MOCK_ENABLED = process.env.NEXT_PUBLIC_CONFIDENCE_ENGINE_MOCKS === "true";
@@ -224,26 +225,23 @@ export default function ScenarioForm() {
 
   /* ── RTO.25A — passive late-result branch switcher (experimental) ── */
 
-  const BRANCHES = [
-    {
-      id: "branch-a",
-      label: "Competitor development",
-      origin: "Whether competitors are developing similar products and when they might release them",
-    },
-    {
-      id: "branch-b",
-      label: "Customer demand",
-      origin: "How many customers will buy the product, and what revenue that represents",
-    },
-  ];
-
   const [activeBranchId, setActiveBranchId] = useState("branch-b");
   const [branchNewResults, setBranchNewResults] = useState({});
 
+  /* ── RTO.26B — experimental branch-scoped reasoning fixture ───── */
+
+  const branchScoped = useBranchScopedFixture();
+  // Toggle to control when the experiment view is visible vs production
+  const [showExperimentView, setShowExperimentView] = useState(
+    typeof window !== "undefined" ? (window.sessionStorage?.getItem("ce-show-experiment") !== "false") : true,
+  );
+
+  // Use fixture branches as the authoritative source when available
+  const BRANCHES = useMemo(() => branchScoped.getBranches(), [branchScoped]);
+
   // Simulate a late semantic result arriving on Branch A ~2s after a graph loads
   useEffect(() => {
     if (status !== "success" && status !== "error") return;
-    // Only simulate once per graph load
     if (branchNewResults["branch-a"]) return;
 
     const timer = setTimeout(() => {
@@ -252,6 +250,29 @@ export default function ScenarioForm() {
     return () => clearTimeout(timer);
   }, [status, branchNewResults]);
 
+  // Compute branch-local data for the active branch (explicit provenance)
+  const activeBranch = BRANCHES.find(b => b.id === activeBranchId);
+  const experimentalBranchQuestions = useMemo(() => {
+    if (!activeBranch) return [];
+    return branchScoped.getBranchQuestions(activeBranch.id);
+  }, [activeBranch, branchScoped]);
+
+  const experimentalBranchContributions = useMemo(() => {
+    if (!activeBranch) return [];
+    return branchScoped.getBranchContributions(activeBranch.id);
+  }, [activeBranch, branchScoped]);
+
+  // Determine which non-active branches have new results for passive indicator
+  const inactiveBranchNewResults = useMemo(() => {
+    const result = {};
+    BRANCHES.forEach(b => {
+      if (b.id !== activeBranchId && b.id in branchNewResults) {
+        result[b.id] = true;
+      }
+    });
+    return result;
+  }, [activeBranchId, BRANCHES, branchNewResults]);
+
   /* Restore persisted session on mount (Phase 3) ─────────── */
   useEffect(() => {
     if (typeof window === "undefined") return;
@@ -417,7 +438,75 @@ export default function ScenarioForm() {
 
   return (
     <div className="space-y-6">
-      {status === "idle" && (
+      {/* ── RTO.26B — standalone branch-scoped experimental view (shown when experiment is active) ───── */}
+      {showExperimentView && status !== "loading" && !result?.situationGraph && !result?.updatedSituationGraph && (
+        <>
+          <PulseStyle />
+          <div className="grid grid-cols-1 gap-6 lg:grid-cols-4">
+            {/* Workspace (3/4) — branch-scoped fixture only, no API needed */}
+            <div className="lg:col-span-3">
+              {(() => {
+                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="idle"
+                    currentUnderstanding={currentUnderstanding}
+                    result={{ situationGraph: null, selectedQuestion: null, newlySurfacedNodeIds: [], diagnostics: null }}
+                    answer=""
+                    setAnswer={() => {}}
+                    onAnswerSubmit={async (e) => e.preventDefault()}
+                    lastSubmittedAnswer=""
+                    branchContext={branchContext}
+                    experimentalBranches={BRANCHES.length > 0 ? BRANCHES : undefined}
+                    branchLocalQuestions={experimentalBranchQuestions.length > 0 ? experimentalBranchQuestions : undefined}
+                    branchLocalContributions={experimentalBranchContributions.length > 0 ? experimentalBranchContributions : undefined}
+                    inactiveBranchNewResults={Object.keys(inactiveBranchNewResults).length > 0 ? inactiveBranchNewResults : undefined}
+                    onRestart={() => { setStatus("idle"); setResult(null); setScenario(""); }}
+                  />
+                );
+              })()}
+            </div>
+
+            {/* Branch switcher (1/4 sidebar) */}
+            <div className="lg:col-span-1">
+              <ExperimentalBranchSwitcher
+                branches={BRANCHES}
+                activeBranchId={activeBranchId}
+                branchNewResults={branchNewResults}
+                onBranchSelect={(id) => {
+                  if (id !== activeBranchId) {
+                    setActiveBranchId(id);
+                  }
+                }}
+              />
+            </div>
+          </div>
+        </>
+      )}
+
+      {/* ── Experiment toggle (visible when experiment is NOT shown) ─ */}
+      {!showExperimentView && status !== "loading" && !result?.updatedSituationGraph && (
+        <div className="rounded-lg border border-gray-200/60 bg-gray-50/30 px-4 py-3 text-center">
+          <p className="text-sm text-gray-500 mb-3">
+            Production view active.
+          </p>
+          <button
+            onClick={() => {
+              setShowExperimentView(true);
+              try { window.sessionStorage?.setItem("ce-show-experiment", "true"); } catch {}
+            }}
+            className="rounded-lg border border-blue-600 bg-white px-4 py-2 text-sm font-medium text-blue-700 hover:bg-blue-50 transition"
+          >
+            Try branch-scoped experiment (RTO.26B)
+          </button>
+        </div>
+      )}
+
+      {/* ── Idle form for scenario input (shown only when experiment is off) ─ */}
+      {!showExperimentView && !result?.situationGraph && status === "idle" && (
         <form onSubmit={handleSubmit} className="space-y-6">
 
           {/* Two-column landing workspace */}
@@ -450,7 +539,7 @@ export default function ScenarioForm() {
                       className="h-4 w-4 rounded border-gray-300 text-blue-600 focus:ring-blue-500"
                     />
                     <label htmlFor="dismiss-facilitator" className="text-xs text-gray-500">
-                      Don't show this introduction again
+                      {`Dismiss this introduction permanently`}
                     </label>
                   </div>
                 </div>
@@ -459,7 +548,7 @@ export default function ScenarioForm() {
 
             {/* Right panel — Workspace (2/3 on desktop) */}
             <div className={hideFacilitatorOnLanding ? "md:col-span-3" : "md:col-span-2"}>
-              <h2 className="mb-4 text-xs font-bold tracking-widest uppercase text-gray-400">Tell me what's happening</h2>
+              <h2 className="mb-4 text-xs font-bold tracking-widest uppercase text-gray-400">What&#39;s the situation</h2>
               <textarea
                 ref={textareaRef}
                 value={scenario}
@@ -537,7 +626,7 @@ export default function ScenarioForm() {
       )}
 
       {/* ── Main result workspace ─────────────────────── */}
-      {((status === "success" || status === "error") && status !== "loading") && (
+      {(status === "success" || status === "error") && (
         <>
           <PulseStyle />
           <div className="grid grid-cols-1 gap-6 lg:grid-cols-4">
@@ -566,6 +655,11 @@ export default function ScenarioForm() {
                     onAnswerSubmit={handleUpdate}
                     lastSubmittedAnswer={lastSubmittedAnswer}
                     branchContext={branchContext}
+                    // ── RTO.26B — branch-local reasoning from explicit provenance ──
+                    experimentalBranches={BRANCHES.length > 0 ? BRANCHES : undefined}
+                    branchLocalQuestions={experimentalBranchQuestions.length > 0 ? experimentalBranchQuestions : undefined}
+                    branchLocalContributions={experimentalBranchContributions.length > 0 ? experimentalBranchContributions : undefined}
+                    inactiveBranchNewResults={Object.keys(inactiveBranchNewResults).length > 0 ? inactiveBranchNewResults : undefined}
                     onRestart={() => {
                   clearSession();
                   setStatus("idle");