feat: add removable reference feature vertical slice

tests/e2e/app-shell.spec.js

@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test";
+import { ROUTE_REGISTRY } from "../../src/features/installed-feature-contracts.js";
 
 test("boots the public app shell", async ({ page }) => {
   await page.goto("/");
@@ -27,7 +28,11 @@ test("navigates to a registry-backed example without a page reload", async ({
 test("opens the protected integration route through the local demo seam", async ({
   page,
 }) => {
-  await page.goto("/sample/resources");
+  const protectedRoute = Object.values(ROUTE_REGISTRY).find(
+    (definition) => definition.access === "integration-defined",
+  );
+  if (!protectedRoute) throw new Error("An integration route is required");
+  await page.goto(protectedRoute.path);
   await expect(
     page.getByRole("heading", { name: "세션이 필요합니다." }),
   ).toBeVisible();
@@ -35,7 +40,7 @@ test("opens the protected integration route through the local demo seam", async
   await page.getByRole("button", { name: "로그인 시작" }).click();
 
   await expect(
-    page.getByRole("heading", { name: "보호된 연동 지점" }),
+    page.getByRole("heading", { name: protectedRoute.title }),
   ).toBeVisible();
   await expect(page.getByText("인증됨")).toBeVisible();
 });