feat(app): locale migration L2 — default-locale App cutover

e2e/app-locale-routes.spec.ts

@@ -3,8 +3,8 @@ import { expect, test } from "@playwright/test";
 /**
  * Smoke tests for public `app/[lang]/*` routes (locale migration L1).
  *
- * URLs use an explicit locale prefix (`/en`, `/de/...`). Unprefixed `/` and
- * `/privacy` remain Pages Router until L2/L3 cutover.
+ * Explicit `/en/*` URLs redirect to unprefixed canonicals in L2; see
+ * `e2e/locale-migration-l2.spec.ts` for unprefixed `/` and `/privacy`.
  */
 test.describe("app/[lang] public routes", () => {
   test("en home is indexable with public canonical", async ({ page }) => {

e2e/helpers/dismissCookieBanner.ts

@@ -0,0 +1,16 @@
+import type { Page } from "@playwright/test";
+
+/** Dismiss the cookie consent banner when present (fresh preview / CI sessions). */
+export async function dismissCookieBannerIfVisible(page: Page): Promise<void> {
+  const rejectButton = page.getByRole("button", {
+    name: /reject non-essential/i,
+  });
+  const isVisible = await rejectButton.isVisible().catch(() => false);
+  if (!isVisible) {
+    return;
+  }
+  await rejectButton.click();
+  await rejectButton
+    .waitFor({ state: "hidden", timeout: 15_000 })
+    .catch(() => undefined);
+}

e2e/locale-migration-l2.spec.ts

@@ -0,0 +1,54 @@
+import { expect, test } from "@playwright/test";
+
+/**
+ * Smoke tests for locale migration L2: unprefixed default-locale URLs serve App
+ * `(default-locale)/*`. Explicit `/en/*` may also serve App `[lang]` with the same canonicals.
+ */
+test.describe("locale migration L2 public URLs", () => {
+  test("unprefixed home is indexable with public canonical", async ({
+    page,
+  }) => {
+    await page.goto("/");
+    await expect(page).toHaveTitle(/dStruct/);
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('meta[name="darkreader-lock"]')).toHaveCount(1);
+    await expect(page.locator('meta[name="theme-color"]')).toHaveAttribute(
+      "content",
+      "#121212",
+    );
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/",
+    );
+  });
+
+  test("unprefixed privacy is indexable with public canonical", async ({
+    page,
+  }) => {
+    await page.goto("/privacy");
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/privacy",
+    );
+  });
+
+  test("unprefixed daily is indexable with public canonical", async ({
+    page,
+  }) => {
+    await page.goto("/daily");
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/daily",
+    );
+  });
+
+  test("explicit /en/privacy serves unprefixed canonical", async ({ page }) => {
+    await page.goto("/en/privacy");
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/privacy",
+    );
+  });
+});

e2e/pilot-routes.spec.ts

@@ -1,5 +1,7 @@
 import { expect, test } from "@playwright/test";
 
+import { dismissCookieBannerIfVisible } from "./helpers/dismissCookieBanner";
+
 /**
  * Smoke tests for `/internal-marketing/[locale]/*` App Router pilots.
  *
@@ -76,7 +78,11 @@ test.describe("internal-marketing pilot routes", () => {
 
   test("pilot home footer links to public privacy page", async ({ page }) => {
     await page.goto("/internal-marketing/en");
-    await page.getByRole("link", { name: /privacy policy/i }).click();
-    await expect(page).toHaveURL(/\/privacy$/);
+    await dismissCookieBannerIfVisible(page);
+    const privacyLink = page
+      .getByRole("contentinfo")
+      .getByRole("link", { name: /privacy policy/i });
+    await privacyLink.scrollIntoViewIfNeeded();
+    await Promise.all([page.waitForURL(/\/privacy$/), privacyLink.click()]);
   });
 });

next-env.d.ts

@@ -2,6 +2,7 @@
 /// <reference types="next/image-types/global" />
 /// <reference types="next/navigation-types/compat/navigation" />
 import "./.next/types/routes.d.ts";
+import "./.next/types/root-params.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

next.config.mjs

@@ -7,30 +7,6 @@ void (
   !process.env.SKIP_ENV_VALIDATION && (await import("./src/env/server.mjs"))
 );
 
-/** Keep in sync with `src/i18n/i18n-util.ts` `locales`. */
-const i18nLocales = [
-  "ar",
-  "be",
-  "de",
-  "en",
-  "es",
-  "fr",
-  "hi",
-  "id",
-  "it",
-  "ja",
-  "ko",
-  "nl",
-  "pl",
-  "pt",
-  "ru",
-  "sr",
-  "tr",
-  "uk",
-  "vi",
-  "zh",
-];
-
 /** @type {import("next").NextConfig} */
 const config = {
   reactStrictMode: true,
@@ -84,11 +60,6 @@ const config = {
     "three",
     "zod",
   ],
-  i18n: {
-    locales: i18nLocales,
-    defaultLocale: "en",
-    localeDetection: false,
-  },
   images: {
     remotePatterns: [
       {

src/app/(default-locale)/daily/page.tsx

@@ -0,0 +1,21 @@
+import type { Metadata } from "next";
+
+import { DailyPageView } from "#/features/homePage/ui/DailyPageView";
+import { baseLocale } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata(): Promise<Metadata> {
+  return publicPageMetadataFromTranslation(
+    baseLocale,
+    "/daily",
+    (translation) => ({
+      title: `${translation.HOME_DAILY_SECTION_TITLE} — dStruct`,
+      description: `${translation.HOME_DAILY_SECTION_TITLE}. ${translation.HOME_DAILY_SECTION_LEAD}`,
+    }),
+  );
+}
+
+export default function DefaultLocaleDailyPage() {
+  return <DailyPageView />;
+}

src/app/(default-locale)/layout.tsx

@@ -0,0 +1,14 @@
+import { baseLocale } from "#/i18n/i18n-util";
+
+import { LocaleAppLayout } from "#/app/locale-app/LocaleAppLayout";
+
+/** Default-locale (`en`) public App shell at unprefixed URLs (L2). */
+export const dynamic = "force-dynamic";
+
+export default async function DefaultLocaleLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return <LocaleAppLayout localeParam={baseLocale}>{children}</LocaleAppLayout>;
+}

src/app/(default-locale)/page.tsx

@@ -0,0 +1,18 @@
+import type { Metadata } from "next";
+
+import { MarketingHomeView } from "#/features/homePage/ui/MarketingHomeView";
+import { baseLocale } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata(): Promise<Metadata> {
+  return publicPageMetadataFromTranslation(baseLocale, "/", (translation) => ({
+    title: translation.SITE_SEO_TITLE,
+    description: translation.SITE_SEO_DESCRIPTION,
+  }));
+}
+
+/** App Router home at `/` (default locale; non-`en` locales use `app/[lang]`). */
+export default function DefaultLocaleHomePage() {
+  return <MarketingHomeView />;
+}

src/app/(default-locale)/playground/[[...slug]]/page.tsx

@@ -0,0 +1,40 @@
+import type { Metadata } from "next";
+import React, { Suspense } from "react";
+
+import { resolvePlaygroundPageSeo } from "#/features/playground/lib/resolvePlaygroundPageSeo";
+import { PlaygroundPageView } from "#/features/playground/ui/PlaygroundPageView";
+import { baseLocale } from "#/i18n/i18n-util";
+import { SplitPanelsLayoutSkeleton } from "#/shared/ui/templates/SplitPanelsLayout/SplitPanelsLayoutSkeleton";
+
+import { publicAppMetadata } from "#/app/locale-app/publicAppMetadata";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ slug?: string[] }>;
+}): Promise<Metadata> {
+  const { slug } = await params;
+  const slugStr = slug?.[0];
+  const pagePath = slugStr ? `/playground/${slugStr}` : "/playground";
+  const { pageTitle, pageDescription } = await resolvePlaygroundPageSeo(
+    baseLocale,
+    slugStr,
+  );
+
+  return publicAppMetadata({
+    locale: baseLocale,
+    pagePath,
+    title: pageTitle,
+    description: pageDescription,
+  });
+}
+
+const PlaygroundFallback: React.FC = () => <SplitPanelsLayoutSkeleton />;
+
+export default function DefaultLocalePlaygroundPage() {
+  return (
+    <Suspense fallback={<PlaygroundFallback />}>
+      <PlaygroundPageView />
+    </Suspense>
+  );
+}

src/app/(default-locale)/privacy/page.tsx

@@ -0,0 +1,21 @@
+import type { Metadata } from "next";
+
+import { PrivacyPageView } from "#/features/privacy/ui/PrivacyPageView";
+import { baseLocale } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata(): Promise<Metadata> {
+  return publicPageMetadataFromTranslation(
+    baseLocale,
+    "/privacy",
+    (translation) => ({
+      title: `${translation.PRIVACY_PAGE_TITLE} — dStruct`,
+      description: translation.PRIVACY_INTRO,
+    }),
+  );
+}
+
+export default function DefaultLocalePrivacyPage() {
+  return <PrivacyPageView />;
+}

src/app/(default-locale)/profile/[userId]/page.tsx

@@ -0,0 +1,42 @@
+import type { Metadata } from "next";
+import { notFound } from "next/navigation";
+
+import { ProfilePageView } from "#/features/profile/ui/ProfilePageView";
+import { baseLocale } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ userId: string }>;
+}): Promise<Metadata> {
+  const { userId } = await params;
+  if (!userId.trim()) {
+    return {};
+  }
+  const pagePath = `/profile/${userId}`;
+
+  return publicPageMetadataFromTranslation(
+    baseLocale,
+    pagePath,
+    (translation) => ({
+      title: `${translation.PROFILE} — dStruct`,
+      description: translation.SITE_SEO_DESCRIPTION,
+    }),
+    { indexable: false },
+  );
+}
+
+export default async function DefaultLocaleProfilePage({
+  params,
+}: {
+  params: Promise<{ userId: string }>;
+}) {
+  const { userId } = await params;
+  if (!userId.trim()) {
+    notFound();
+  }
+
+  return <ProfilePageView />;
+}

src/app/[lang]/page.tsx

@@ -24,8 +24,7 @@ export async function generateMetadata({
 }
 
 /**
- * App Router home at `/{lang}` (e.g. `/en`, `/de`).
- * Default-locale public `/` remains Pages until locale migration L2/L3.
+ * App Router home at `/{lang}` (e.g. `/de`). Default-locale `/` uses `(default-locale)`.
  */
 export default function LangHomePage() {
   return <MarketingHomeView />;

src/app/internal-marketing/[locale]/page.tsx

@@ -26,10 +26,7 @@ export async function generateMetadata({
   }));
 }
 
-/**
- * Instant Nav pilot (App Router). Public home remains Pages `pages/index`
- * until locale routing leaves `next.config` `i18n`.
- */
+/** Instant Nav pilot (App Router). Public home is `app/(default-locale)` / `app/[lang]`. */
 export default function InternalMarketingHomePage() {
   return <MarketingHomeView />;
 }

src/app/layout.tsx

@@ -33,6 +33,8 @@ export default async function RootLayout({
   return (
     <html lang={locale} dir={htmlDir} className={fontVariableClassNames}>
       <head>
+        {/* Parity with `pages/_document.tsx` — Dark Reader must see this literal empty meta. */}
+        <meta name="darkreader-lock" />
         <link rel="preconnect" href="https://fonts.googleapis.com" />
         <link
           rel="preconnect"

src/features/homePage/ui/MarketingHomeView.tsx

@@ -1,8 +1,7 @@
 "use client";
 
 /**
- * Marketing home UI. Public `/` uses Pages `pages/index`; App Router
- * `internal-marketing/[locale]` reuses this for the Instant Nav pilot.
+ * Marketing home UI. Public `/` and `app/[lang]` reuse this; internal-marketing pilot too.
  */
 import { useState } from "react";
 

src/i18n/__tests__/localeMigrationRouting.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, it } from "vitest";
+
+import { isDefaultLocalePublicMarketingPath } from "#/i18n/localeMigrationRouting";
+
+describe("localeMigrationRouting", () => {
+  it("detects default-locale public marketing paths", () => {
+    expect(isDefaultLocalePublicMarketingPath("/")).toBe(true);
+    expect(isDefaultLocalePublicMarketingPath("/privacy")).toBe(true);
+    expect(isDefaultLocalePublicMarketingPath("/playground/foo")).toBe(true);
+    expect(isDefaultLocalePublicMarketingPath("/profile/u1")).toBe(true);
+    expect(isDefaultLocalePublicMarketingPath("/de")).toBe(false);
+    expect(isDefaultLocalePublicMarketingPath("/api/trpc")).toBe(false);
+  });
+});

src/i18n/localeMigrationRouting.ts

@@ -0,0 +1,16 @@
+/** Unprefixed default-locale marketing paths served by App `(default-locale)` (L2). */
+export function isDefaultLocalePublicMarketingPath(pathname: string): boolean {
+  if (pathname === "/") {
+    return true;
+  }
+  if (pathname === "/privacy" || pathname === "/daily") {
+    return true;
+  }
+  if (pathname === "/playground" || pathname.startsWith("/playground/")) {
+    return true;
+  }
+  if (pathname.startsWith("/profile/")) {
+    return true;
+  }
+  return false;
+}