feat(app): public app/[lang] routes — locale migration L1

AGENTS.md

@@ -1,15 +1,10 @@
 <!-- BEGIN:nextjs-agent-rules -->
 
-# Next.js: ALWAYS read docs before coding
+# This is NOT the Next.js you know
 
-Before any Next.js work, find and read the relevant doc in `node_modules/next/dist/docs/`. Your training data is outdated — the docs are the source of truth.
+This version has breaking changes — APIs, conventions, and file structure may all differ from your training data. Read the relevant guide in `node_modules/next/dist/docs/` (resolved from this file's directory; in monorepos the `next` package may not be visible from the repo root) before writing any code. Heed deprecation notices.
 
-Good starting points in the bundle:
-
-- `01-app/02-guides/ai-agents.md` — agent setup and doc layout
-- `01-app/01-getting-started/` — App Router basics
-- `01-app/03-api-reference/` — APIs and file conventions
-- `02-pages/` — **Pages Router** (this repo uses `src/pages/` — prefer this tree for `getServerSideProps`, API routes, and `next.config` under `02-pages/04-api-reference/`)
+This block is written and re-added by `next dev` — verify at `node_modules/next/dist/server/lib/generate-agent-files.js`. Removing it from a diff only re-creates the uncommitted change; committing it with your work keeps the tree clean.
 
 <!-- END:nextjs-agent-rules -->
 

e2e/app-locale-routes.spec.ts

@@ -0,0 +1,63 @@
+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.
+ */
+test.describe("app/[lang] public routes", () => {
+  test("en home is indexable with public canonical", async ({ page }) => {
+    await page.goto("/en");
+    await expect(page).toHaveTitle(/dStruct/);
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/",
+    );
+  });
+
+  test("en privacy is indexable with public canonical", async ({ page }) => {
+    await page.goto("/en/privacy");
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/privacy",
+    );
+  });
+
+  test("de daily is indexable with locale canonical", async ({ page }) => {
+    await page.goto("/de/daily");
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/de/daily",
+    );
+  });
+
+  test("en playground landing is indexable with public canonical", async ({
+    page,
+  }) => {
+    await page.goto("/en/playground");
+    await expect(page).toHaveTitle(/Playground/i);
+    await expect(page.locator('meta[name="robots"]')).toHaveCount(0);
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      "https://dstruct.pro/playground",
+    );
+  });
+
+  test("en profile is noindex with public canonical", async ({ page }) => {
+    const userId = "e2e-app-lang-user";
+    await page.goto(`/en/profile/${userId}`);
+    await expect(page).toHaveTitle(/Profile/i);
+    await expect(page.locator('meta[name="robots"]')).toHaveAttribute(
+      "content",
+      /noindex/i,
+    );
+    await expect(page.locator('link[rel="canonical"]')).toHaveAttribute(
+      "href",
+      `https://dstruct.pro/profile/${userId}`,
+    );
+  });
+});

src/app/[lang]/daily/page.tsx

@@ -0,0 +1,28 @@
+import type { Metadata } from "next";
+
+import { DailyPageView } from "#/features/homePage/ui/DailyPageView";
+import type { Locales } from "#/i18n/i18n-types";
+import { locales } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ lang: string }>;
+}): Promise<Metadata> {
+  const { lang: langParam } = await params;
+  if (!locales.includes(langParam as Locales)) {
+    return {};
+  }
+  const locale = langParam as Locales;
+
+  return publicPageMetadataFromTranslation(locale, "/daily", (translation) => ({
+    title: `${translation.HOME_DAILY_SECTION_TITLE} — dStruct`,
+    description: `${translation.HOME_DAILY_SECTION_TITLE}. ${translation.HOME_DAILY_SECTION_LEAD}`,
+  }));
+}
+
+export default function LangDailyPage() {
+  return <DailyPageView />;
+}

src/app/[lang]/layout.tsx

@@ -0,0 +1,15 @@
+import { LocaleAppLayout } from "#/app/locale-app/LocaleAppLayout";
+
+/** Locale marketing + app shell under `app/[lang]` (L1; Pages `i18n` still canonical for unprefixed `en` URLs). */
+export const dynamic = "force-dynamic";
+
+export default async function LangLayout({
+  children,
+  params,
+}: {
+  children: React.ReactNode;
+  params: Promise<{ lang: string }>;
+}) {
+  const { lang } = await params;
+  return <LocaleAppLayout localeParam={lang}>{children}</LocaleAppLayout>;
+}

src/app/[lang]/page.tsx

@@ -0,0 +1,32 @@
+import type { Metadata } from "next";
+
+import { MarketingHomeView } from "#/features/homePage/ui/MarketingHomeView";
+import type { Locales } from "#/i18n/i18n-types";
+import { locales } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ lang: string }>;
+}): Promise<Metadata> {
+  const { lang: langParam } = await params;
+  if (!locales.includes(langParam as Locales)) {
+    return {};
+  }
+  const locale = langParam as Locales;
+
+  return publicPageMetadataFromTranslation(locale, "/", (translation) => ({
+    title: translation.SITE_SEO_TITLE,
+    description: translation.SITE_SEO_DESCRIPTION,
+  }));
+}
+
+/**
+ * App Router home at `/{lang}` (e.g. `/en`, `/de`).
+ * Default-locale public `/` remains Pages until locale migration L2/L3.
+ */
+export default function LangHomePage() {
+  return <MarketingHomeView />;
+}

src/app/[lang]/playground/[[...slug]]/page.tsx

@@ -0,0 +1,45 @@
+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 type { Locales } from "#/i18n/i18n-types";
+import { locales } 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<{ lang: string; slug?: string[] }>;
+}): Promise<Metadata> {
+  const { lang: langParam, slug } = await params;
+  if (!locales.includes(langParam as Locales)) {
+    return {};
+  }
+  const locale = langParam as Locales;
+  const slugStr = slug?.[0];
+  const pagePath = slugStr ? `/playground/${slugStr}` : "/playground";
+  const { pageTitle, pageDescription } = await resolvePlaygroundPageSeo(
+    locale,
+    slugStr,
+  );
+
+  return publicAppMetadata({
+    locale,
+    pagePath,
+    title: pageTitle,
+    description: pageDescription,
+  });
+}
+
+const PlaygroundFallback: React.FC = () => <SplitPanelsLayoutSkeleton />;
+
+export default function LangPlaygroundPage() {
+  return (
+    <Suspense fallback={<PlaygroundFallback />}>
+      <PlaygroundPageView />
+    </Suspense>
+  );
+}

src/app/[lang]/privacy/page.tsx

@@ -0,0 +1,32 @@
+import type { Metadata } from "next";
+
+import { PrivacyPageView } from "#/features/privacy/ui/PrivacyPageView";
+import type { Locales } from "#/i18n/i18n-types";
+import { locales } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ lang: string }>;
+}): Promise<Metadata> {
+  const { lang: langParam } = await params;
+  if (!locales.includes(langParam as Locales)) {
+    return {};
+  }
+  const locale = langParam as Locales;
+
+  return publicPageMetadataFromTranslation(
+    locale,
+    "/privacy",
+    (translation) => ({
+      title: `${translation.PRIVACY_PAGE_TITLE} — dStruct`,
+      description: translation.PRIVACY_INTRO,
+    }),
+  );
+}
+
+export default function LangPrivacyPage() {
+  return <PrivacyPageView />;
+}

src/app/[lang]/profile/[userId]/page.tsx

@@ -0,0 +1,44 @@
+import type { Metadata } from "next";
+import { notFound } from "next/navigation";
+
+import { ProfilePageView } from "#/features/profile/ui/ProfilePageView";
+import type { Locales } from "#/i18n/i18n-types";
+import { locales } from "#/i18n/i18n-util";
+
+import { publicPageMetadataFromTranslation } from "#/app/locale-app/publicPageMetadataFromTranslation";
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ lang: string; userId: string }>;
+}): Promise<Metadata> {
+  const { lang: langParam, userId } = await params;
+  if (!locales.includes(langParam as Locales) || !userId.trim()) {
+    return {};
+  }
+  const locale = langParam as Locales;
+  const pagePath = `/profile/${userId}`;
+
+  return publicPageMetadataFromTranslation(
+    locale,
+    pagePath,
+    (translation) => ({
+      title: `${translation.PROFILE} — dStruct`,
+      description: translation.SITE_SEO_DESCRIPTION,
+    }),
+    { indexable: false },
+  );
+}
+
+export default async function LangProfilePage({
+  params,
+}: {
+  params: Promise<{ lang: string; userId: string }>;
+}) {
+  const { userId } = await params;
+  if (!userId.trim()) {
+    notFound();
+  }
+
+  return <ProfilePageView />;
+}

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

@@ -1,13 +1,8 @@
 import type { Metadata } from "next";
-import { getServerSession } from "next-auth";
-import { notFound } from "next/navigation";
 
-import type { Locales } from "#/i18n/i18n-types";
 import { locales } from "#/i18n/i18n-util";
-import { loadI18nForLocale } from "#/i18n/loadI18nForLocale";
-import { authOptions } from "#/server/auth/authOptions";
 
-import { AppRootLayoutClient } from "#/app/AppRootLayoutClient";
+import { LocaleAppLayout } from "#/app/locale-app/LocaleAppLayout";
 
 /** All pilot routes stay noindex even when a child page omits metadata. */
 export const metadata: Metadata = {
@@ -25,16 +20,11 @@ export default async function InternalMarketingLocaleLayout({
   params: Promise<{ locale: string }>;
 }) {
   const { locale: localeParam } = await params;
-  if (!locales.includes(localeParam as Locales)) {
-    notFound();
-  }
-  const locale = localeParam as Locales;
-  const session = await getServerSession(authOptions);
-  const i18n = await loadI18nForLocale(locale);
-
   return (
-    <AppRootLayoutClient session={session} i18n={i18n} locale={locale}>
-      {children}
-    </AppRootLayoutClient>
+    <LocaleAppLayout localeParam={localeParam}>{children}</LocaleAppLayout>
   );
 }
+
+export function generateStaticParams(): Array<{ locale: string }> {
+  return locales.map((locale) => ({ locale }));
+}

src/app/locale-app/LocaleAppLayout.tsx

@@ -0,0 +1,31 @@
+import { getServerSession } from "next-auth";
+import { notFound } from "next/navigation";
+
+import type { Locales } from "#/i18n/i18n-types";
+import { locales } from "#/i18n/i18n-util";
+import { loadI18nForLocale } from "#/i18n/loadI18nForLocale";
+import { authOptions } from "#/server/auth/authOptions";
+
+import { AppRootLayoutClient } from "#/app/AppRootLayoutClient";
+
+/** Shared App Router locale layout for `app/[lang]` and internal-marketing pilot. */
+export async function LocaleAppLayout({
+  children,
+  localeParam,
+}: {
+  children: React.ReactNode;
+  localeParam: string;
+}) {
+  if (!locales.includes(localeParam as Locales)) {
+    notFound();
+  }
+  const locale = localeParam as Locales;
+  const session = await getServerSession(authOptions);
+  const i18n = await loadI18nForLocale(locale);
+
+  return (
+    <AppRootLayoutClient session={session} i18n={i18n} locale={locale}>
+      {children}
+    </AppRootLayoutClient>
+  );
+}

src/app/locale-app/__tests__/publicAppMetadata.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from "vitest";
+
+import { publicAppMetadata } from "#/app/locale-app/publicAppMetadata";
+
+describe("publicAppMetadata", () => {
+  it("sets indexable canonical for default-locale home via /en path", () => {
+    const metadata = publicAppMetadata({
+      locale: "en",
+      pagePath: "/",
+      title: "dStruct",
+      description: "Test description",
+    });
+
+    expect(metadata.robots).toBeUndefined();
+    expect(metadata.alternates?.canonical).toBe("https://dstruct.pro/");
+    expect(metadata.title).toBe("dStruct");
+  });
+
+  it("uses locale-prefixed canonical for non-default locales", () => {
+    const metadata = publicAppMetadata({
+      locale: "de",
+      pagePath: "/privacy",
+      title: "Privacy",
+      description: "Intro",
+    });
+
+    expect(metadata.alternates?.canonical).toBe(
+      "https://dstruct.pro/de/privacy",
+    );
+  });
+
+  it("emits noindex when indexable is false", () => {
+    const metadata = publicAppMetadata({
+      locale: "en",
+      pagePath: "/profile/user-1",
+      title: "Profile",
+      description: "Intro",
+      indexable: false,
+    });
+
+    expect(metadata.robots).toEqual({ index: false, follow: true });
+  });
+});