Increase complexity of test demo

packages/core-v2/README.md

@@ -21,16 +21,20 @@ From the workspace root:
 npm run dev:v2
 ```
 
-Open the printed URL to explore seven physical labs:
+Open the printed URL to explore nine physical labs:
 
 - a four-view chain that can keep four nodes and three edges live at once;
 - one view with horizontal, vertical, and edge-only declarations;
 - programmatic gallery navigation followed by gesture-owned traversal;
 - a vertically presented media player with local interactive state;
 - a chat that intentionally declares no back gesture;
-- a predicate-gated downward gesture that drops a left-edge dialog.
+- a predicate-gated downward gesture that drops a left-edge dialog;
 - three nested scenes demonstrating cooperative carousels, vertical decks, and
-  an intentional parent/child gesture conflict.
+  an intentional parent/child gesture conflict; and
+- a checkout flow that replaces Payment Details with Confirmation and proves
+  that back returns directly to the retained Hub instance; and
+- a connected two-thirds drawer that keeps the translated source page visible
+  in the exposed final third.
 
 The expandable inspector reports mounted Vue instances, active operation
 edges, animation progress, and recent lifecycle events. In the chain lab,
@@ -156,6 +160,46 @@ The application chooses whether this is exposed as a left-edge gesture,
 toolbar button, keyboard shortcut, Android hardware-back action, or not exposed
 at all.
 
+## Replacing the current entry
+
+Use `replace()` for completed one-way flows such as Payment Details →
+Confirmation:
+
+```ts
+import {
+  originView,
+  replace,
+  slideLeft,
+  useOrigin,
+} from "@native-vue-router/core-v2";
+import OrderConfirmationView from "./OrderConfirmationView.vue";
+
+const origin = useOrigin();
+
+function confirmOrder() {
+  return origin.perform(
+    replace(
+      originView(OrderConfirmationView, { orderId: "NVO-2048" }),
+      slideLeft,
+    ),
+  );
+}
+```
+
+The replacement inherits the current entry's mounted predecessor. It does not
+retain the entry being replaced, so back from Confirmation skips Payment
+Details. The mutation is atomic: a cancelled interactive replacement removes
+the proposed Confirmation and restores Payment Details unchanged.
+
+Inside a gesture builder, omit choreography from the intent:
+
+```ts
+gesture.to
+  .left()
+  .navigate(() => replace(originView(OrderConfirmationView)))
+  .animate(slideLeft);
+```
+
 ## Custom choreography
 
 A choreography returns independent effects for its source, target, and their
@@ -195,6 +239,23 @@ Y transform = (X→Y target) × (Y→Z source)
 Z transform = (X→Y target) × (Y→Z target)
 ```
 
+For partial presentations that must keep both views visible after commit, set
+`persistAtRest: true` on the opening choreography:
+
+```ts
+const openDrawer = defineOriginChoreography({
+  persistAtRest: true,
+  effects: ({ progress }) => ({
+    source: { transform: `translateX(${progress * 66.6667}%)` },
+    target: { transform: `translateX(${(progress - 1) * 66.6667}%)` },
+  }),
+});
+```
+
+The retained source becomes visible-but-inert rather than parked. A reciprocal
+back choreography closes the target; a cancelled close restores the connected
+resting effects and both original Vue instances.
+
 ## Why scene nodes are flat
 
 The operation graph is not represented as Vue component ancestry. Every