test: authenticated admin E2E tour with smart mock backend (all pages screenshot)

- Rewrote e2e/mock-backend.mjs to return valid auth responses (login + refresh)
- Created e2e/authenticated-tour.spec.ts that logs in and screenshots all 7 admin pages
- Fixed (dashboard-layout)/layout.tsx: added missing NextIntlClientProvider
- All pages render error-free in dark mode with mock data
- Screenshots: dashboard, members, distributions, distribution/new, stock, stock/new, reports

cannamanage-frontend/src/app/(dashboard-layout)/layout.tsx

@@ -1,3 +1,6 @@
+import { NextIntlClientProvider } from "next-intl"
+import { getMessages } from "next-intl/server"
+
 import { Layout } from "@/components/layout"
 
 export default async function DashboardLayout({
@@ -5,5 +8,11 @@ export default async function DashboardLayout({
 }: {
   children: React.ReactNode
 }) {
-  return <Layout>{children}</Layout>
+  const messages = await getMessages()
+
+  return (
+    <NextIntlClientProvider messages={messages}>
+      <Layout>{children}</Layout>
+    </NextIntlClientProvider>
+  )
 }