feat: rebuild landing experience, content and analytics

app/components/cinematic/CinematicHome.test.tsx

@@ -28,6 +28,7 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+  jest.restoreAllMocks();
   window.history.replaceState(null, "", "/");
   if (originalScrollIntoView) {
     HTMLElement.prototype.scrollIntoView = originalScrollIntoView;
@@ -37,6 +38,37 @@ afterEach(() => {
 });
 
 describe("home fragment navigation", () => {
+  it("starts an unfragmented visit at the top after the notebook establishes layout", () => {
+    let restoredPosition = 3200;
+    jest
+      .spyOn(window, "scrollTo")
+      .mockImplementation((options: ScrollToOptions | number) => {
+        if (typeof options === "object")
+          restoredPosition = options.top ?? restoredPosition;
+      });
+    render(<HomeNavigation />);
+    fireEvent.click(
+      screen.getByRole("button", { name: "Establish notebook layout" }),
+    );
+    expect(restoredPosition).toBe(0);
+  });
+
+  it("does not reset the visitor's position after intentional scrolling during startup", () => {
+    let position = 0;
+    jest
+      .spyOn(window, "scrollTo")
+      .mockImplementation((options: ScrollToOptions | number) => {
+        if (typeof options === "object") position = options.top ?? position;
+      });
+    render(<HomeNavigation />);
+    position = 600;
+    fireEvent.wheel(window, { deltaY: 600 });
+    fireEvent.click(
+      screen.getByRole("button", { name: "Establish notebook layout" }),
+    );
+    expect(position).toBe(600);
+  });
+
   it("waits for the notebook layout on fragment arrival, then never steals focus on refresh", () => {
     window.history.replaceState(null, "", "/#contact");
     render(<HomeNavigation />);