feat(web-i18n): add es/fr locales and expand switcher locale set

TODO.md

@@ -21,12 +21,12 @@ This file is the single source of truth for roadmap and delivery progress.
 - [x] [P1] RBAC domain model finalized (roles, permissions, resource scopes)
 - [x] [P1] RBAC enforcement at route and action level in admin
 - [x] [P1] Permission matrix documented and tested
-- [ ] [P1] i18n baseline architecture (default locale, supported locales, routing strategy)
-- [ ] [P1] i18n runtime integration baseline for both apps (locale provider + message loading)
-- [ ] [P1] Locale persistence and switcher base component (cookie/header + UI)
+- [~] [P1] i18n baseline architecture (default locale, supported locales, routing strategy)
+- [~] [P1] i18n runtime integration baseline for both apps (locale provider + message loading)
+- [~] [P1] Locale persistence and switcher base component (cookie/header + UI)
 - [x] [P1] Integrate Better Auth core configuration and session wiring
 - [x] [P1] Bootstrap first-run owner account creation via initial registration flow
-- [ ] [P1] Enforce invariant: exactly one owner user must always exist
+- [x] [P1] Enforce invariant: exactly one owner user must always exist
 - [x] [P1] Create hidden technical support user by default (non-demotable, non-deletable)
 - [~] [P1] Admin registration policy control (allow/deny self-registration for admin panel)
 - [x] [P1] First-start onboarding route for initial owner creation (`/welcome`)
@@ -115,7 +115,7 @@ This file is the single source of truth for roadmap and delivery progress.
 - [ ] [P1] Media refinement for artworks (medium, dimensions, year, framing, availability)
 - [ ] [P1] Users management (invite, roles, status)
 - [ ] [P1] Disable/ban user function and enforcement in auth/session checks
-- [ ] [P1] Owner/support protection rules in user management actions (cannot delete/demote)
+- [~] [P1] Owner/support protection rules in user management actions (cannot delete/demote)
 - [ ] [P1] Commissions management (request intake, owner, due date, notes)
 - [ ] [P1] Kanban workflow for commissions (new, scoped, in-progress, review, done)
 - [ ] [P1] Header banner management (message, CTA, active window)
@@ -191,6 +191,9 @@ This file is the single source of truth for roadmap and delivery progress.
 - [2026-02-10] Linux Playwright runtime depends on host packages; browser setup may require `playwright install --with-deps`.
 - [2026-02-10] Next.js 16 deprecates `middleware.ts` convention in favor of `proxy.ts`; admin route guard now lives at `apps/admin/src/proxy.ts`.
 - [2026-02-10] `server-only` imports break Bun CLI scripts; shared auth bootstrap code used by scripts must avoid Next-only runtime markers.
+- [2026-02-10] Auth delete-account endpoints now block protected users (support + canonical owner); admin user-management delete/demote guards remain to be implemented.
+- [2026-02-10] Public app i18n baseline now uses `next-intl` with a Zustand-backed language switcher and path-stable routes; admin i18n runtime is still pending.
+- [2026-02-10] Public baseline locales are now `de`, `en`, `es`, `fr`; locale enable/disable policy will move to admin settings later.
 
 ## How We Use This File
 

apps/admin/src/app/api/auth/[...all]/route.ts

@@ -1,5 +1,7 @@
 import {
+  auth,
   authRouteHandlers,
+  canDeleteUserAccount,
   canUserSelfRegister,
   ensureSupportUserBootstrap,
   ensureUserUsername,
@@ -40,6 +42,51 @@ function buildJsonRequest(request: Request, body: Record<string, unknown>): Requ
   })
 }
 
+function isDeleteUserAuthPath(pathname: string): boolean {
+  const actionPrefix = "/api/auth/"
+  const actionIndex = pathname.indexOf(actionPrefix)
+
+  if (actionIndex === -1) {
+    return false
+  }
+
+  const actionPath = pathname.slice(actionIndex + actionPrefix.length)
+  return actionPath === "delete-user" || actionPath.startsWith("delete-user/")
+}
+
+async function guardProtectedAccountDeletion(request: Request): Promise<Response | null> {
+  const pathname = new URL(request.url).pathname
+
+  if (!isDeleteUserAuthPath(pathname)) {
+    return null
+  }
+
+  const session = await auth.api
+    .getSession({
+      headers: request.headers,
+    })
+    .catch(() => null)
+
+  const userId = session?.user?.id
+
+  if (!userId) {
+    return null
+  }
+
+  const allowed = await canDeleteUserAccount(userId)
+
+  if (allowed) {
+    return null
+  }
+
+  return jsonResponse(
+    {
+      message: "This account is protected and cannot be deleted.",
+    },
+    403,
+  )
+}
+
 async function handleSignInPost(request: Request): Promise<Response> {
   await ensureSupportUserBootstrap()
 
@@ -136,6 +183,13 @@ async function handleSignUpPost(request: Request): Promise<Response> {
 
 export async function GET(request: Request): Promise<Response> {
   await ensureSupportUserBootstrap()
+
+  const deletionGuardResponse = await guardProtectedAccountDeletion(request)
+
+  if (deletionGuardResponse) {
+    return deletionGuardResponse
+  }
+
   return authRouteHandlers.GET(request)
 }
 
@@ -151,20 +205,48 @@ export async function POST(request: Request): Promise<Response> {
   }
 
   await ensureSupportUserBootstrap()
+
+  const deletionGuardResponse = await guardProtectedAccountDeletion(request)
+
+  if (deletionGuardResponse) {
+    return deletionGuardResponse
+  }
+
   return authRouteHandlers.POST(request)
 }
 
 export async function PATCH(request: Request): Promise<Response> {
   await ensureSupportUserBootstrap()
+
+  const deletionGuardResponse = await guardProtectedAccountDeletion(request)
+
+  if (deletionGuardResponse) {
+    return deletionGuardResponse
+  }
+
   return authRouteHandlers.PATCH(request)
 }
 
 export async function PUT(request: Request): Promise<Response> {
   await ensureSupportUserBootstrap()
+
+  const deletionGuardResponse = await guardProtectedAccountDeletion(request)
+
+  if (deletionGuardResponse) {
+    return deletionGuardResponse
+  }
+
   return authRouteHandlers.PUT(request)
 }
 
 export async function DELETE(request: Request): Promise<Response> {
   await ensureSupportUserBootstrap()
+
+  const deletionGuardResponse = await guardProtectedAccountDeletion(request)
+
+  if (deletionGuardResponse) {
+    return deletionGuardResponse
+  }
+
   return authRouteHandlers.DELETE(request)
 }

apps/admin/src/lib/auth/server.ts

@@ -359,7 +359,10 @@ export async function ensureSupportUserBootstrap(): Promise<void> {
     return
   }
 
-  supportBootstrapPromise = bootstrapSystemUsers()
+  supportBootstrapPromise = (async () => {
+    await bootstrapSystemUsers()
+    await enforceOwnerInvariant()
+  })()
 
   try {
     await supportBootstrapPromise
@@ -369,8 +372,116 @@ export async function ensureSupportUserBootstrap(): Promise<void> {
   }
 }
 
-export async function promoteFirstRegisteredUserToOwner(userId: string): Promise<boolean> {
+type OwnerInvariantState = {
+  ownerId: string | null
+  ownerCount: number
+  repaired: boolean
+}
+
+export async function enforceOwnerInvariant(): Promise<OwnerInvariantState> {
   return db.$transaction(async (tx) => {
+    const owners = await tx.user.findMany({
+      where: { role: "owner" },
+      orderBy: [{ createdAt: "asc" }, { id: "asc" }],
+      select: { id: true, isProtected: true, isBanned: true },
+    })
+
+    if (owners.length === 0) {
+      const candidate = await tx.user.findFirst({
+        where: {
+          role: {
+            not: "support",
+          },
+        },
+        orderBy: [{ createdAt: "asc" }, { id: "asc" }],
+        select: { id: true },
+      })
+
+      if (!candidate) {
+        return {
+          ownerId: null,
+          ownerCount: 0,
+          repaired: false,
+        }
+      }
+
+      await tx.user.update({
+        where: { id: candidate.id },
+        data: {
+          role: "owner",
+          isProtected: true,
+          isBanned: false,
+        },
+      })
+
+      return {
+        ownerId: candidate.id,
+        ownerCount: 1,
+        repaired: true,
+      }
+    }
+
+    const canonicalOwner = owners[0]
+    const extraOwnerIds = owners.slice(1).map((owner) => owner.id)
+
+    if (extraOwnerIds.length > 0) {
+      await tx.user.updateMany({
+        where: { id: { in: extraOwnerIds } },
+        data: {
+          role: "admin",
+          isProtected: false,
+        },
+      })
+    }
+
+    if (!canonicalOwner.isProtected || canonicalOwner.isBanned) {
+      await tx.user.update({
+        where: { id: canonicalOwner.id },
+        data: {
+          isProtected: true,
+          isBanned: false,
+        },
+      })
+    }
+
+    return {
+      ownerId: canonicalOwner.id,
+      ownerCount: 1,
+      repaired: extraOwnerIds.length > 0 || !canonicalOwner.isProtected || canonicalOwner.isBanned,
+    }
+  })
+}
+
+export async function canDeleteUserAccount(userId: string): Promise<boolean> {
+  const user = await db.user.findUnique({
+    where: { id: userId },
+    select: { role: true, isProtected: true },
+  })
+
+  if (!user) {
+    return false
+  }
+
+  // Protected/system users (support + canonical owner) are never deletable
+  // through self-service endpoints.
+  if (user.isProtected) {
+    return false
+  }
+
+  if (user.role !== "owner") {
+    return true
+  }
+
+  // Defensive fallback for drifted data; normal flow should already keep one owner.
+  const ownerCount = await db.user.count({
+    where: { role: "owner" },
+  })
+
+  return ownerCount > 1
+}
+
+export async function promoteFirstRegisteredUserToOwner(userId: string): Promise<boolean> {
+  const promoted = await db.$transaction(async (tx) => {
     const existingOwner = await tx.user.findFirst({
       where: { role: "owner" },
       select: { id: true },
@@ -393,6 +504,12 @@ export async function promoteFirstRegisteredUserToOwner(userId: string): Promise
 
     return true
   })
+
+  if (promoted) {
+    await enforceOwnerInvariant()
+  }
+
+  return promoted
 }
 
 export function resolveRoleFromAuthSession(session: AuthSession | null | undefined): Role | null {

apps/web/next.config.ts

@@ -1,7 +1,10 @@
 import type { NextConfig } from "next"
+import createNextIntlPlugin from "next-intl/plugin"
+
+const withNextIntl = createNextIntlPlugin("./src/i18n/request.ts")
 
 const nextConfig: NextConfig = {
-  transpilePackages: ["@cms/ui", "@cms/content", "@cms/db"],
+  transpilePackages: ["@cms/ui", "@cms/content", "@cms/db", "@cms/i18n"],
 }
 
-export default nextConfig
+export default withNextIntl(nextConfig)

apps/web/package.json

@@ -13,10 +13,12 @@
   "dependencies": {
     "@cms/content": "workspace:*",
     "@cms/db": "workspace:*",
+    "@cms/i18n": "workspace:*",
     "@cms/ui": "workspace:*",
     "@tanstack/react-query": "5.90.20",
     "@tanstack/react-query-devtools": "5.91.3",
     "next": "16.1.6",
+    "next-intl": "4.4.0",
     "react": "19.2.4",
     "react-dom": "19.2.4",
     "zustand": "5.0.11"

apps/web/src/app/[locale]/layout.tsx

@@ -0,0 +1,27 @@
+import { notFound } from "next/navigation"
+import { hasLocale, NextIntlClientProvider } from "next-intl"
+import type { ReactNode } from "react"
+
+import { routing } from "@/i18n/routing"
+import { Providers } from "../providers"
+
+type LocaleLayoutProps = {
+  children: ReactNode
+  params: Promise<{
+    locale: string
+  }>
+}
+
+export default async function LocaleLayout({ children, params }: LocaleLayoutProps) {
+  const { locale } = await params
+
+  if (!hasLocale(routing.locales, locale)) {
+    notFound()
+  }
+
+  return (
+    <NextIntlClientProvider locale={locale}>
+      <Providers>{children}</Providers>
+    </NextIntlClientProvider>
+  )
+}

apps/web/src/app/[locale]/page.tsx

@@ -1,25 +1,29 @@
 import { listPosts } from "@cms/db"
 import { Button } from "@cms/ui/button"
+import { getTranslations } from "next-intl/server"
+
+import { LanguageSwitcher } from "@/components/language-switcher"
 
 export const dynamic = "force-dynamic"
 
 export default async function HomePage() {
-  const posts = await listPosts()
+  const [posts, t] = await Promise.all([listPosts(), getTranslations("Home")])
 
   return (
     <main className="mx-auto flex min-h-screen w-full max-w-3xl flex-col gap-6 px-6 py-16">
       <header className="space-y-3">
-        <p className="text-sm uppercase tracking-[0.2em] text-neutral-500">Web App</p>
-        <h1 className="text-4xl font-semibold tracking-tight">Your Next.js CMS Frontend</h1>
-        <p className="text-neutral-600">
-          This page reads posts through the shared database package.
-        </p>
+        <div className="flex flex-wrap items-center justify-between gap-3">
+          <p className="text-sm uppercase tracking-[0.2em] text-neutral-500">{t("badge")}</p>
+          <LanguageSwitcher />
+        </div>
+        <h1 className="text-4xl font-semibold tracking-tight">{t("title")}</h1>
+        <p className="text-neutral-600">{t("description")}</p>
       </header>
 
       <section className="space-y-4 rounded-xl border border-neutral-200 p-6">
         <div className="flex items-center justify-between">
-          <h2 className="text-xl font-medium">Latest posts</h2>
-          <Button variant="secondary">Explore</Button>
+          <h2 className="text-xl font-medium">{t("latestPosts")}</h2>
+          <Button variant="secondary">{t("explore")}</Button>
         </div>
 
         <ul className="space-y-3">
@@ -27,7 +31,7 @@ export default async function HomePage() {
             <li key={post.id} className="rounded-lg border border-neutral-200 p-4">
               <p className="text-xs uppercase tracking-wide text-neutral-500">{post.status}</p>
               <h3 className="mt-1 text-lg font-medium">{post.title}</h3>
-              <p className="mt-2 text-sm text-neutral-600">{post.excerpt ?? "No excerpt"}</p>
+              <p className="mt-2 text-sm text-neutral-600">{post.excerpt ?? t("noExcerpt")}</p>
             </li>
           ))}
         </ul>

apps/web/src/app/layout.tsx

@@ -2,7 +2,6 @@ import type { Metadata } from "next"
 import type { ReactNode } from "react"
 
 import "./globals.css"
-import { Providers } from "./providers"
 
 export const metadata: Metadata = {
   title: "CMS Web",
@@ -12,9 +11,7 @@ export const metadata: Metadata = {
 export default function RootLayout({ children }: { children: ReactNode }) {
   return (
     <html lang="en">
-      <body>
-        <Providers>{children}</Providers>
-      </body>
+      <body>{children}</body>
     </html>
   )
 }

apps/web/src/components/language-switcher.tsx

@@ -0,0 +1,50 @@
+"use client"
+
+import { type AppLocale, localeLabels, locales } from "@cms/i18n"
+import { useLocale, useTranslations } from "next-intl"
+import { useEffect, useTransition } from "react"
+
+import { usePathname, useRouter } from "@/i18n/navigation"
+import { useLocaleStore } from "@/store/locale"
+
+export function LanguageSwitcher() {
+  const t = useTranslations("LanguageSwitcher")
+  const currentLocale = useLocale() as AppLocale
+  const pathname = usePathname()
+  const router = useRouter()
+  const [isPending, startTransition] = useTransition()
+
+  const locale = useLocaleStore((state) => state.locale)
+  const setLocale = useLocaleStore((state) => state.setLocale)
+
+  useEffect(() => {
+    if (locale !== currentLocale) {
+      setLocale(currentLocale)
+    }
+  }, [currentLocale, locale, setLocale])
+
+  return (
+    <label className="inline-flex items-center gap-2 text-sm text-neutral-700">
+      <span>{t("label")}</span>
+      <select
+        className="rounded-md border border-neutral-300 bg-white px-2 py-1 text-sm"
+        value={locale}
+        disabled={isPending}
+        onChange={(event) => {
+          const nextLocale = event.target.value as AppLocale
+          setLocale(nextLocale)
+
+          startTransition(() => {
+            router.replace(pathname, { locale: nextLocale })
+          })
+        }}
+      >
+        {locales.map((value) => (
+          <option key={value} value={value}>
+            {t(`localeNames.${value}`)} ({localeLabels[value]})
+          </option>
+        ))}
+      </select>
+    </label>
+  )
+}

apps/web/src/i18n/navigation.ts

@@ -0,0 +1,5 @@
+import { createNavigation } from "next-intl/navigation"
+
+import { routing } from "./routing"
+
+export const { Link, redirect, usePathname, useRouter, getPathname } = createNavigation(routing)

apps/web/src/i18n/request.ts

@@ -0,0 +1,14 @@
+import { hasLocale } from "next-intl"
+import { getRequestConfig } from "next-intl/server"
+
+import { routing } from "./routing"
+
+export default getRequestConfig(async ({ requestLocale }) => {
+  const requested = await requestLocale
+  const locale = hasLocale(routing.locales, requested) ? requested : routing.defaultLocale
+
+  return {
+    locale,
+    messages: (await import(`../messages/${locale}.json`)).default,
+  }
+})

apps/web/src/i18n/routing.ts

@@ -0,0 +1,8 @@
+import { defaultLocale, locales } from "@cms/i18n"
+import { defineRouting } from "next-intl/routing"
+
+export const routing = defineRouting({
+  locales: [...locales],
+  defaultLocale,
+  localePrefix: "never",
+})

apps/web/src/messages/de.json

@@ -0,0 +1,19 @@
+{
+  "Home": {
+    "badge": "Web-App",
+    "title": "Dein Next.js CMS Frontend",
+    "description": "Diese Seite liest Beiträge über das gemeinsame Datenbank-Paket.",
+    "latestPosts": "Neueste Beiträge",
+    "explore": "Entdecken",
+    "noExcerpt": "Kein Auszug"
+  },
+  "LanguageSwitcher": {
+    "label": "Sprache",
+    "localeNames": {
+      "de": "Deutsch",
+      "en": "Englisch",
+      "es": "Spanisch",
+      "fr": "Französisch"
+    }
+  }
+}

apps/web/src/messages/en.json

@@ -0,0 +1,19 @@
+{
+  "Home": {
+    "badge": "Web App",
+    "title": "Your Next.js CMS Frontend",
+    "description": "This page reads posts through the shared database package.",
+    "latestPosts": "Latest posts",
+    "explore": "Explore",
+    "noExcerpt": "No excerpt"
+  },
+  "LanguageSwitcher": {
+    "label": "Language",
+    "localeNames": {
+      "de": "German",
+      "en": "English",
+      "es": "Spanish",
+      "fr": "French"
+    }
+  }
+}

apps/web/src/messages/es.json

@@ -0,0 +1,19 @@
+{
+  "Home": {
+    "badge": "Aplicación Web",
+    "title": "Tu Frontend CMS con Next.js",
+    "description": "Esta página lee publicaciones a través del paquete compartido de base de datos.",
+    "latestPosts": "Últimas publicaciones",
+    "explore": "Explorar",
+    "noExcerpt": "Sin extracto"
+  },
+  "LanguageSwitcher": {
+    "label": "Idioma",
+    "localeNames": {
+      "de": "Alemán",
+      "en": "Inglés",
+      "es": "Español",
+      "fr": "Francés"
+    }
+  }
+}

apps/web/src/messages/fr.json

@@ -0,0 +1,19 @@
+{
+  "Home": {
+    "badge": "Application Web",
+    "title": "Votre Frontend CMS Next.js",
+    "description": "Cette page lit les publications via le package base de données partagé.",
+    "latestPosts": "Dernières publications",
+    "explore": "Explorer",
+    "noExcerpt": "Aucun extrait"
+  },
+  "LanguageSwitcher": {
+    "label": "Langue",
+    "localeNames": {
+      "de": "Allemand",
+      "en": "Anglais",
+      "es": "Espagnol",
+      "fr": "Français"
+    }
+  }
+}

apps/web/src/proxy.ts

@@ -0,0 +1,14 @@
+import type { NextRequest } from "next/server"
+import createMiddleware from "next-intl/middleware"
+
+import { routing } from "@/i18n/routing"
+
+const handleI18nRouting = createMiddleware(routing)
+
+export function proxy(request: NextRequest) {
+  return handleI18nRouting(request)
+}
+
+export const config = {
+  matcher: ["/((?!api|trpc|_next|_vercel|.*\\..*).*)"],
+}

apps/web/src/store/locale.test.ts

@@ -0,0 +1,12 @@
+import { describe, expect, it } from "vitest"
+
+import { useLocaleStore } from "./locale"
+
+describe("web locale store", () => {
+  it("sets locale", () => {
+    useLocaleStore.setState({ locale: "en" })
+    useLocaleStore.getState().setLocale("de")
+
+    expect(useLocaleStore.getState().locale).toBe("de")
+  })
+})

apps/web/src/store/locale.ts

@@ -0,0 +1,12 @@
+import { type AppLocale, defaultLocale } from "@cms/i18n"
+import { create } from "zustand"
+
+type LocaleStore = {
+  locale: AppLocale
+  setLocale: (value: AppLocale) => void
+}
+
+export const useLocaleStore = create<LocaleStore>((set) => ({
+  locale: defaultLocale,
+  setLocale: (value) => set({ locale: value }),
+}))

bun.lock

@@ -5,23 +5,23 @@
     "": {
       "name": "cms-monorepo",
       "devDependencies": {
-        "@biomejs/biome": "latest",
-        "@commitlint/cli": "latest",
-        "@commitlint/config-conventional": "latest",
-        "@playwright/test": "latest",
-        "@testing-library/jest-dom": "latest",
-        "@testing-library/react": "latest",
-        "@testing-library/user-event": "latest",
-        "@vitejs/plugin-react": "latest",
-        "@vitest/coverage-istanbul": "latest",
-        "conventional-changelog-cli": "latest",
-        "jsdom": "latest",
-        "msw": "latest",
-        "turbo": "latest",
-        "typescript": "latest",
-        "vite-tsconfig-paths": "latest",
-        "vitepress": "latest",
-        "vitest": "latest",
+        "@biomejs/biome": "2.3.14",
+        "@commitlint/cli": "20.4.1",
+        "@commitlint/config-conventional": "20.4.1",
+        "@playwright/test": "1.58.2",
+        "@testing-library/jest-dom": "6.9.1",
+        "@testing-library/react": "16.3.2",
+        "@testing-library/user-event": "14.6.1",
+        "@vitejs/plugin-react": "5.1.3",
+        "@vitest/coverage-istanbul": "4.0.18",
+        "conventional-changelog-cli": "5.0.0",
+        "jsdom": "28.0.0",
+        "msw": "2.12.9",
+        "turbo": "2.8.3",
+        "typescript": "5.9.3",
+        "vite-tsconfig-paths": "6.1.0",
+        "vitepress": "1.6.4",
+        "vitest": "4.0.18",
       },
     },
     "apps/admin": {
@@ -31,25 +31,25 @@
         "@cms/content": "workspace:*",
         "@cms/db": "workspace:*",
         "@cms/ui": "workspace:*",
-        "@tanstack/react-form": "latest",
-        "@tanstack/react-query": "latest",
-        "@tanstack/react-query-devtools": "latest",
-        "@tanstack/react-table": "latest",
+        "@tanstack/react-form": "1.28.0",
+        "@tanstack/react-query": "5.90.20",
+        "@tanstack/react-query-devtools": "5.91.3",
+        "@tanstack/react-table": "8.21.3",
         "better-auth": "1.4.18",
-        "next": "latest",
-        "react": "latest",
-        "react-dom": "latest",
-        "zustand": "latest",
+        "next": "16.1.6",
+        "react": "19.2.4",
+        "react-dom": "19.2.4",
+        "zustand": "5.0.11",
       },
       "devDependencies": {
-        "@biomejs/biome": "latest",
+        "@biomejs/biome": "2.3.14",
         "@cms/config": "workspace:*",
-        "@tailwindcss/postcss": "latest",
-        "@types/node": "latest",
-        "@types/react": "latest",
-        "@types/react-dom": "latest",
-        "tailwindcss": "latest",
-        "typescript": "latest",
+        "@tailwindcss/postcss": "4.1.18",
+        "@types/node": "25.2.2",
+        "@types/react": "19.2.13",
+        "@types/react-dom": "19.2.3",
+        "tailwindcss": "4.1.18",
+        "typescript": "5.9.3",
       },
     },
     "apps/web": {
@@ -58,23 +58,25 @@
       "dependencies": {
         "@cms/content": "workspace:*",
         "@cms/db": "workspace:*",
+        "@cms/i18n": "workspace:*",
         "@cms/ui": "workspace:*",
-        "@tanstack/react-query": "latest",
-        "@tanstack/react-query-devtools": "latest",
-        "next": "latest",
-        "react": "latest",
-        "react-dom": "latest",
-        "zustand": "latest",
+        "@tanstack/react-query": "5.90.20",
+        "@tanstack/react-query-devtools": "5.91.3",
+        "next": "16.1.6",
+        "next-intl": "4.4.0",
+        "react": "19.2.4",
+        "react-dom": "19.2.4",
+        "zustand": "5.0.11",
       },
       "devDependencies": {
-        "@biomejs/biome": "latest",
+        "@biomejs/biome": "2.3.14",
         "@cms/config": "workspace:*",
-        "@tailwindcss/postcss": "latest",
-        "@types/node": "latest",
-        "@types/react": "latest",
-        "@types/react-dom": "latest",
-        "tailwindcss": "latest",
-        "typescript": "latest",
+        "@tailwindcss/postcss": "4.1.18",
+        "@types/node": "25.2.2",
+        "@types/react": "19.2.13",
+        "@types/react-dom": "19.2.3",
+        "tailwindcss": "4.1.18",
+        "typescript": "5.9.3",
       },
     },
     "packages/config": {
@@ -85,12 +87,12 @@
       "name": "@cms/content",
       "version": "0.0.1",
       "dependencies": {
-        "zod": "latest",
+        "zod": "4.3.6",
       },
       "devDependencies": {
-        "@biomejs/biome": "latest",
+        "@biomejs/biome": "2.3.14",
         "@cms/config": "workspace:*",
-        "typescript": "latest",
+        "typescript": "5.9.3",
       },
     },
     "packages/db": {
@@ -98,39 +100,47 @@
       "version": "0.0.1",
       "dependencies": {
         "@cms/content": "workspace:*",
-        "@prisma/adapter-pg": "latest",
-        "@prisma/client": "latest",
-        "pg": "latest",
-        "zod": "latest",
+        "@prisma/adapter-pg": "7.3.0",
+        "@prisma/client": "7.3.0",
+        "pg": "8.18.0",
+        "zod": "4.3.6",
       },
       "devDependencies": {
-        "@biomejs/biome": "latest",
+        "@biomejs/biome": "2.3.14",
         "@cms/config": "workspace:*",
-        "@types/node": "latest",
-        "@types/pg": "latest",
-        "better-auth": "1.4.18",
-        "prisma": "latest",
-        "typescript": "latest",
+        "@types/node": "25.2.2",
+        "@types/pg": "8.16.0",
+        "prisma": "7.3.0",
+        "typescript": "5.9.3",
+      },
+    },
+    "packages/i18n": {
+      "name": "@cms/i18n",
+      "version": "0.0.1",
+      "devDependencies": {
+        "@biomejs/biome": "2.3.14",
+        "@cms/config": "workspace:*",
+        "typescript": "5.9.3",
       },
     },
     "packages/ui": {
       "name": "@cms/ui",
       "version": "0.0.1",
       "dependencies": {
-        "class-variance-authority": "latest",
-        "clsx": "latest",
-        "tailwind-merge": "latest",
+        "class-variance-authority": "0.7.1",
+        "clsx": "2.1.1",
+        "tailwind-merge": "3.4.0",
       },
       "devDependencies": {
-        "@biomejs/biome": "latest",
+        "@biomejs/biome": "2.3.14",
         "@cms/config": "workspace:*",
-        "@types/react": "latest",
-        "@types/react-dom": "latest",
-        "typescript": "latest",
+        "@types/react": "19.2.13",
+        "@types/react-dom": "19.2.3",
+        "typescript": "5.9.3",
       },
       "peerDependencies": {
-        "react": "latest",
-        "react-dom": "latest",
+        "react": "19.2.4",
+        "react-dom": "19.2.4",
       },
     },
   },
@@ -265,6 +275,8 @@
 
     "@cms/db": ["@cms/db@workspace:packages/db"],
 
+    "@cms/i18n": ["@cms/i18n@workspace:packages/i18n"],
+
     "@cms/ui": ["@cms/ui@workspace:packages/ui"],
 
     "@cms/web": ["@cms/web@workspace:apps/web"],
@@ -385,6 +397,16 @@
 
     "@exodus/bytes": ["@exodus/bytes@1.12.0", "", { "peerDependencies": { "@noble/hashes": "^1.8.0 || ^2.0.0" }, "optionalPeers": ["@noble/hashes"] }, "sha512-BuCOHA/EJdPN0qQ5MdgAiJSt9fYDHbghlgrj33gRdy/Yp1/FMCDhU6vJfcKrLC0TPWGSrfH3vYXBQWmFHxlddw=="],
 
+    "@formatjs/ecma402-abstract": ["@formatjs/ecma402-abstract@3.1.1", "", { "dependencies": { "@formatjs/fast-memoize": "3.1.0", "@formatjs/intl-localematcher": "0.8.1", "decimal.js": "^10.6.0", "tslib": "^2.8.1" } }, "sha512-jhZbTwda+2tcNrs4kKvxrPLPjx8QsBCLCUgrrJ/S+G9YrGHWLhAyFMMBHJBnBoOwuLHd7L14FgYudviKaxkO2Q=="],
+
+    "@formatjs/fast-memoize": ["@formatjs/fast-memoize@3.1.0", "", { "dependencies": { "tslib": "^2.8.1" } }, "sha512-b5mvSWCI+XVKiz5WhnBCY3RJ4ZwfjAidU0yVlKa3d3MSgKmH1hC3tBGEAtYyN5mqL7N0G5x0BOUYyO8CEupWgg=="],
+
+    "@formatjs/icu-messageformat-parser": ["@formatjs/icu-messageformat-parser@3.5.1", "", { "dependencies": { "@formatjs/ecma402-abstract": "3.1.1", "@formatjs/icu-skeleton-parser": "2.1.1", "tslib": "^2.8.1" } }, "sha512-sSDmSvmmoVQ92XqWb499KrIhv/vLisJU8ITFrx7T7NZHUmMY7EL9xgRowAosaljhqnj/5iufG24QrdzB6X3ItA=="],
+
+    "@formatjs/icu-skeleton-parser": ["@formatjs/icu-skeleton-parser@2.1.1", "", { "dependencies": { "@formatjs/ecma402-abstract": "3.1.1", "tslib": "^2.8.1" } }, "sha512-PSFABlcNefjI6yyk8f7nyX1DC7NHmq6WaCHZLySEXBrXuLOB2f935YsnzuPjlz+ibhb9yWTdPeVX1OVcj24w2Q=="],
+
+    "@formatjs/intl-localematcher": ["@formatjs/intl-localematcher@0.5.10", "", { "dependencies": { "tslib": "2" } }, "sha512-af3qATX+m4Rnd9+wHcjJ4w2ijq+rAVP3CCinJQvFv1kgSu1W6jypUmvleJxcewdxmutM8dmIRZFxO/IQBZmP2Q=="],
+
     "@hono/node-server": ["@hono/node-server@1.19.9", "", { "peerDependencies": { "hono": "^4" } }, "sha512-vHL6w3ecZsky+8P5MD+eFfaGTyCeOHUIFYMGpQGbrBTSmNNoxv0if69rEZ5giu36weC5saFuznL411gRX7bJDw=="],
 
     "@hutson/parse-repository-url": ["@hutson/parse-repository-url@5.0.0", "", {}, "sha512-e5+YUKENATs1JgYHMzTr2MW/NDcXGfYFAuOQU8gJgF/kEh4EqKgfGrfLI67bMD4tbhZVlkigz/9YYwWcbOFthg=="],
@@ -577,6 +599,8 @@
 
     "@rollup/rollup-win32-x64-msvc": ["@rollup/rollup-win32-x64-msvc@4.57.1", "", { "os": "win32", "cpu": "x64" }, "sha512-mxRFDdHIWRxg3UfIIAwCm6NzvxG0jDX/wBN6KsQFTvKFqqg9vTrWUE68qEjHt19A5wwx5X5aUi2zuZT7YR0jrA=="],
 
+    "@schummar/icu-type-parser": ["@schummar/icu-type-parser@1.21.5", "", {}, "sha512-bXHSaW5jRTmke9Vd0h5P7BtWZG9Znqb8gSDxZnxaGSJnGwPLDPfS+3g0BKzeWqzgZPsIVZkM7m2tbo18cm5HBw=="],
+
     "@shikijs/core": ["@shikijs/core@2.5.0", "", { "dependencies": { "@shikijs/engine-javascript": "2.5.0", "@shikijs/engine-oniguruma": "2.5.0", "@shikijs/types": "2.5.0", "@shikijs/vscode-textmate": "^10.0.2", "@types/hast": "^3.0.4", "hast-util-to-html": "^9.0.4" } }, "sha512-uu/8RExTKtavlpH7XqnVYBrfBkUc20ngXiX9NSrBhOVZYv/7XQRKUyhtkeflY5QsxC0GbJThCerruZfsUaSldg=="],
 
     "@shikijs/engine-javascript": ["@shikijs/engine-javascript@2.5.0", "", { "dependencies": { "@shikijs/types": "2.5.0", "@shikijs/vscode-textmate": "^10.0.2", "oniguruma-to-es": "^3.1.0" } }, "sha512-VjnOpnQf8WuCEZtNUdjjwGUbtAVKuZkVQ/5cHy/tojVVRIRtlWMYVjyWhxOmIq05AlSOv72z7hRNRGVBgQOl0w=="],
@@ -1015,6 +1039,8 @@
 
     "iconv-lite": ["iconv-lite@0.7.2", "", { "dependencies": { "safer-buffer": ">= 2.1.2 < 3.0.0" } }, "sha512-im9DjEDQ55s9fL4EYzOAv0yMqmMBSZp6G0VvFyTMPKWxiSBHUj9NW/qqLmXUwXrrM7AvqSlTCfvqRb0cM8yYqw=="],
 
+    "icu-minify": ["icu-minify@4.8.2", "", { "dependencies": { "@formatjs/icu-messageformat-parser": "^3.4.0" } }, "sha512-LHBQV+skKkjZSPd590pZ7ZAHftUgda3eFjeuNwA8/15L8T8loCNBktKQyTlkodAU86KovFXeg/9WntlAo5wA5A=="],
+
     "import-fresh": ["import-fresh@3.3.1", "", { "dependencies": { "parent-module": "^1.0.0", "resolve-from": "^4.0.0" } }, "sha512-TR3KfrTZTYLPB6jUjfx6MF9WcWrHL9su5TObK4ZkYgBdWKPOFoSoQIdEuTuR82pmtxH2spWG9h6etwfr1pLBqQ=="],
 
     "import-meta-resolve": ["import-meta-resolve@4.2.0", "", {}, "sha512-Iqv2fzaTQN28s/FwZAoFq0ZSs/7hMAHJVX+w8PZl3cY19Pxk6jFFalxQoIfW2826i/fDLXv8IiEZRIT0lDuWcg=="],
@@ -1025,6 +1051,8 @@
 
     "ini": ["ini@4.1.1", "", {}, "sha512-QQnnxNyfvmHFIsj7gkPcYymR8Jdw/o7mp5ZFihxn6h8Ci6fh3Dx4E1gPjpQEpIuPo9XVNY/ZUwh4BPMjGyL01g=="],
 
+    "intl-messageformat": ["intl-messageformat@11.1.2", "", { "dependencies": { "@formatjs/ecma402-abstract": "3.1.1", "@formatjs/fast-memoize": "3.1.0", "@formatjs/icu-messageformat-parser": "3.5.1", "tslib": "^2.8.1" } }, "sha512-ucSrQmZGAxfiBHfBRXW/k7UC8MaGFlEj4Ry1tKiDcmgwQm1y3EDl40u+4VNHYomxJQMJi9NEI3riDRlth96jKg=="],
+
     "is-arrayish": ["is-arrayish@0.2.1", "", {}, "sha512-zz06S8t0ozoDXMG+ube26zeCTNXcKIPJZJi8hBrF4idCLms4CG9QtK7qBl1boi5ODzFpjswb5JPmHCbMpjaYzg=="],
 
     "is-fullwidth-code-point": ["is-fullwidth-code-point@3.0.0", "", {}, "sha512-zymm5+u+sCsSWyD9qNaejV3DFvhCKclKdizYaJUuHA83RLjb7nSuGnddCHGv0hk+KY7BMAlsWeK4Ueg6EV6XQg=="],
@@ -1167,10 +1195,14 @@
 
     "nanostores": ["nanostores@1.1.0", "", {}, "sha512-yJBmDJr18xy47dbNVlHcgdPrulSn1nhSE6Ns9vTG+Nx9VPT6iV1MD6aQFp/t52zpf82FhLLTXAXr30NuCnxvwA=="],
 
+    "negotiator": ["negotiator@1.0.0", "", {}, "sha512-8Ofs/AUQh8MaEcrlq5xOX0CQ9ypTF5dl78mjlMNfOK08fzpgTHQRQPBxcPlEtIw0yRpws+Zo/3r+5WRby7u3Gg=="],
+
     "neo-async": ["neo-async@2.6.2", "", {}, "sha512-Yd3UES5mWCSqR+qNT93S3UoYUkqAZ9lLg8a7g9rimsWmYGK8cVToA4/sF3RrshdyV3sAGMXVUmpMYOw+dLpOuw=="],
 
     "next": ["next@16.1.6", "", { "dependencies": { "@next/env": "16.1.6", "@swc/helpers": "0.5.15", "baseline-browser-mapping": "^2.8.3", "caniuse-lite": "^1.0.30001579", "postcss": "8.4.31", "styled-jsx": "5.1.6" }, "optionalDependencies": { "@next/swc-darwin-arm64": "16.1.6", "@next/swc-darwin-x64": "16.1.6", "@next/swc-linux-arm64-gnu": "16.1.6", "@next/swc-linux-arm64-musl": "16.1.6", "@next/swc-linux-x64-gnu": "16.1.6", "@next/swc-linux-x64-musl": "16.1.6", "@next/swc-win32-arm64-msvc": "16.1.6", "@next/swc-win32-x64-msvc": "16.1.6", "sharp": "^0.34.4" }, "peerDependencies": { "@opentelemetry/api": "^1.1.0", "@playwright/test": "^1.51.1", "babel-plugin-react-compiler": "*", "react": "^18.2.0 || 19.0.0-rc-de68d2f4-20241204 || ^19.0.0", "react-dom": "^18.2.0 || 19.0.0-rc-de68d2f4-20241204 || ^19.0.0", "sass": "^1.3.0" }, "optionalPeers": ["@opentelemetry/api", "@playwright/test", "babel-plugin-react-compiler", "sass"], "bin": { "next": "dist/bin/next" } }, "sha512-hkyRkcu5x/41KoqnROkfTm2pZVbKxvbZRuNvKXLRXxs3VfyO0WhY50TQS40EuKO9SW3rBj/sF3WbVwDACeMZyw=="],
 
+    "next-intl": ["next-intl@4.4.0", "", { "dependencies": { "@formatjs/intl-localematcher": "^0.5.4", "negotiator": "^1.0.0", "use-intl": "^4.4.0" }, "peerDependencies": { "next": "^12.0.0 || ^13.0.0 || ^14.0.0 || ^15.0.0 || ^16.0.0", "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || >=19.0.0-rc <19.0.0 || ^19.0.0", "typescript": "^5.0.0" }, "optionalPeers": ["typescript"] }, "sha512-QHqnP9V9Pe7Tn0PdVQ7u1Z8k9yCkW5SJKeRy2g5gxzhSt/C01y3B9qNxuj3Fsmup/yreIHe6osxU6sFa+9WIkQ=="],
+
     "node-fetch-native": ["node-fetch-native@1.6.7", "", {}, "sha512-g9yhqoedzIUm0nTnTqAQvueMPVOuIY16bqgAJJC8XOOubYFNwz6IER9qs0Gq2Xd0+CecCKFjtdDTMA4u4xG06Q=="],
 
     "node-releases": ["node-releases@2.0.27", "", {}, "sha512-nmh3lCkYZ3grZvqcCH+fjmQ7X+H0OeZgP40OierEaAptX4XofMh5kwNbWh7lBduUzCcV/8kZ+NDLCwm2iorIlA=="],
@@ -1443,6 +1475,8 @@
 
     "update-browserslist-db": ["update-browserslist-db@1.2.3", "", { "dependencies": { "escalade": "^3.2.0", "picocolors": "^1.1.1" }, "peerDependencies": { "browserslist": ">= 4.21.0" }, "bin": { "update-browserslist-db": "cli.js" } }, "sha512-Js0m9cx+qOgDxo0eMiFGEueWztz+d4+M3rGlmKPT+T4IS/jP4ylw3Nwpu6cpTTP8R1MAC1kF4VbdLt3ARf209w=="],
 
+    "use-intl": ["use-intl@4.8.2", "", { "dependencies": { "@formatjs/fast-memoize": "^3.1.0", "@schummar/icu-type-parser": "1.21.5", "icu-minify": "^4.8.2", "intl-messageformat": "^11.1.0" }, "peerDependencies": { "react": "^17.0.0 || ^18.0.0 || >=19.0.0-rc <19.0.0 || ^19.0.0" } }, "sha512-3VNXZgDnPFqhIYosQ9W1Hc6K5q+ZelMfawNbexdwL/dY7BTHbceLUBX5Eeex9lgogxTp0pf1SjHuhYNAjr9H3g=="],
+
     "use-sync-external-store": ["use-sync-external-store@1.6.0", "", { "peerDependencies": { "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0" } }, "sha512-Pp6GSwGP/NrPIrxVFAIkOQeyw8lFenOHijQWkUTrDvrF4ALqylP2C/KCkeS9dpUM3KvYRQhna5vt7IL95+ZQ9w=="],
 
     "valibot": ["valibot@1.2.0", "", { "peerDependencies": { "typescript": ">=5" }, "optionalPeers": ["typescript"] }, "sha512-mm1rxUsmOxzrwnX5arGS+U4T25RdvpPjPN4yR0u9pUBov9+zGVtO84tif1eY4r6zWxVxu3KzIyknJy3rxfRZZg=="],
@@ -1509,6 +1543,8 @@
 
     "@conventional-changelog/git-client/semver": ["semver@7.7.4", "", { "bin": { "semver": "bin/semver.js" } }, "sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA=="],
 
+    "@formatjs/ecma402-abstract/@formatjs/intl-localematcher": ["@formatjs/intl-localematcher@0.8.1", "", { "dependencies": { "@formatjs/fast-memoize": "3.1.0", "tslib": "^2.8.1" } }, "sha512-xwEuwQFdtSq1UKtQnyTZWC+eHdv7Uygoa+H2k/9uzBVQjDyp9r20LNDNKedWXll7FssT3GRHvqsdJGYSUWqYFA=="],
+
     "@inquirer/core/wrap-ansi": ["wrap-ansi@6.2.0", "", { "dependencies": { "ansi-styles": "^4.0.0", "string-width": "^4.1.0", "strip-ansi": "^6.0.0" } }, "sha512-r6lPcBGxZXlIcymEu7InxDMhdW0KDxpLgoFLcguasxCaJ/SOIZwINatK9KY/tf+ZrlywOKU0UDj3ATXUBfxJXA=="],
 
     "@prisma/engines/@prisma/get-platform": ["@prisma/get-platform@7.3.0", "", { "dependencies": { "@prisma/debug": "7.3.0" } }, "sha512-N7c6m4/I0Q6JYmWKP2RCD/sM9eWiyCPY98g5c0uEktObNSZnugW2U/PO+pwL0UaqzxqTXt7gTsYsb0FnMnJNbg=="],

docs/.vitepress/config.mts

@@ -20,6 +20,7 @@ export default defineConfig({
           { text: "Getting Started", link: "/getting-started" },
           { text: "Architecture", link: "/architecture" },
           { text: "Better Auth Baseline", link: "/product-engineering/auth-baseline" },
+          { text: "i18n Baseline", link: "/product-engineering/i18n-baseline" },
           { text: "RBAC And Permissions", link: "/product-engineering/rbac-permission-model" },
           { text: "Workflow", link: "/workflow" },
         ],

docs/architecture.md

@@ -7,6 +7,7 @@
 - `packages/db`: prisma + data access
 - `packages/content`: shared schemas and domain contracts
 - `packages/ui`: shared UI layer
+- `packages/i18n`: shared locale definitions and i18n helpers
 - `packages/config`: shared TS config
 
 ## Design Principles
@@ -14,6 +15,7 @@
 - Shared contracts before feature implementation
 - RBAC and CRUD base as prerequisites for MVP1 feature work
 - Keep admin and public responsibilities clearly separated
+- Public routing is path-stable; locale is resolved via `next-intl` middleware + cookie
 
 ## Pending Documentation
 

docs/getting-started.md

@@ -39,6 +39,7 @@ bun run dev
 ```
 
 - Web: `http://localhost:3000`
+- Web locale switching: use the language switcher in the page header
 - Admin: `http://localhost:3001`
 - Admin welcome (first start): `http://localhost:3001/welcome`
 - Admin login: `http://localhost:3001/login`

docs/product-engineering/auth-baseline.md

@@ -12,6 +12,8 @@ Implemented in MVP0:
 - Support fallback sign-in page: `/support/<CMS_SUPPORT_LOGIN_KEY>`
 - Prisma auth models (`user`, `session`, `account`, `verification`)
 - First registration creates owner; subsequent registrations are disabled
+- Owner invariant reconciliation is enforced in auth bootstrap and owner promotion flow
+- Protected accounts (support + canonical owner) are blocked from delete-account auth endpoints
 
 ## Environment
 
@@ -38,5 +40,5 @@ Optional:
 - Support user bootstrap is available via `bun run auth:seed:support`.
 - Root `bun run db:seed` runs DB seed and support-user seed.
 - `CMS_ADMIN_SELF_REGISTRATION_ENABLED` is temporary until admin settings UI manages this policy.
-- Owner invariant hardening for all future user-management mutations remains tracked in `TODO.md`.
+- Owner/support checks for future admin user-management mutations remain tracked in `TODO.md`.
 - Email verification and forgot/reset password pipelines are tracked for MVP2.

docs/product-engineering/i18n-baseline.md

@@ -0,0 +1,20 @@
+# i18n Baseline
+
+## Scope
+
+MVP0 introduces i18n runtime only for the public app (`@cms/web`) using `next-intl`.
+
+Current baseline:
+
+- Shared locale contract in `@cms/i18n` (`de`, `en`, `es`, `fr`; default `en`)
+- Path-stable routing (no locale in URL) via `apps/web/src/proxy.ts`
+- Message loading through `apps/web/src/i18n/request.ts`
+- Locale-aware navigation helpers in `apps/web/src/i18n/navigation.ts`
+- Public language switcher component backed by Zustand store
+
+## Notes
+
+- Public app locale is resolved through `next-intl` middleware + cookie.
+- Enabled locales are currently static in code and will later be managed from admin settings.
+- Admin app i18n provider/message loading is still pending.
+- Translation key conventions and workflow docs are tracked in `TODO.md`.

packages/i18n/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "@cms/i18n",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "lint": "biome check src",
+    "typecheck": "tsc -p tsconfig.json --noEmit"
+  },
+  "devDependencies": {
+    "@cms/config": "workspace:*",
+    "@biomejs/biome": "2.3.14",
+    "typescript": "5.9.3"
+  }
+}

packages/i18n/src/index.ts

@@ -0,0 +1,16 @@
+export const locales = ["de", "en", "es", "fr"] as const
+
+export type AppLocale = (typeof locales)[number]
+
+export const defaultLocale: AppLocale = "en"
+
+export const localeLabels: Record<AppLocale, string> = {
+  de: "Deutsch",
+  en: "English",
+  es: "Español",
+  fr: "Français",
+}
+
+export function isAppLocale(value: string): value is AppLocale {
+  return locales.includes(value as AppLocale)
+}

packages/i18n/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "@cms/config/tsconfig/base",
+  "compilerOptions": {
+    "noEmit": false,
+    "outDir": "dist"
+  },
+  "include": ["src/**/*.ts"]
+}