feat: assemble responsive app shell navigation

tests/e2e/app-shell.spec.js

@@ -5,4 +5,51 @@ test("boots the public app shell", async ({ page }) => {
   await expect(page.getByRole("heading", { level: 1 })).toHaveText(
     "Clean Architecture Frontend",
   );
+  await expect(page.getByRole("navigation", { name: "주요 탐색" })).toBeVisible();
+  await expect(page.getByRole("main")).toBeVisible();
+});
+
+test("navigates to a registry-backed example without a page reload", async ({
+  page,
+}) => {
+  await page.goto("/");
+  await page
+    .getByRole("navigation", { name: "주요 탐색" })
+    .getByRole("link", { name: "화면 상태" })
+    .click();
+
+  await expect(page).toHaveURL(/\/examples\/states$/);
+  await expect(
+    page.getByRole("heading", { level: 1, name: "화면 상태" }),
+  ).toBeFocused();
+});
+
+test("opens the protected integration route through the local demo seam", async ({
+  page,
+}) => {
+  await page.goto("/sample/resources");
+  await expect(
+    page.getByRole("heading", { name: "세션이 필요합니다." }),
+  ).toBeVisible();
+
+  await page.getByRole("button", { name: "로그인 시작" }).click();
+
+  await expect(
+    page.getByRole("heading", { name: "보호된 연동 지점" }),
+  ).toBeVisible();
+  await expect(page.getByText("인증됨")).toBeVisible();
+});
+
+test("provides an escape-dismissible mobile navigation", async ({ page }) => {
+  await page.setViewportSize({ width: 390, height: 844 });
+  await page.goto("/");
+  const menu = page.getByRole("button", { name: "메뉴", exact: true });
+
+  await menu.click();
+  await expect(menu).toHaveAttribute("aria-expanded", "true");
+  await expect(page.getByRole("navigation", { name: "주요 탐색" })).toBeVisible();
+
+  await page.keyboard.press("Escape");
+  await expect(menu).toHaveAttribute("aria-expanded", "false");
+  await expect(page.getByRole("navigation", { name: "주요 탐색" })).toBeHidden();
 });