Remove next-intl localization infrastructure

Strips out the i18n layer (next-intl, message files, language switcher,
provider) to reduce complexity. Nav components now use plain English strings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/shared/language-switcher.tsx

@@ -1,61 +0,0 @@
-'use client'
-
-import { useTransition } from 'react'
-import { useLocale } from 'next-intl'
-import { useRouter } from 'next/navigation'
-import { Button } from '@/components/ui/button'
-import {
-  DropdownMenu,
-  DropdownMenuContent,
-  DropdownMenuItem,
-  DropdownMenuTrigger,
-} from '@/components/ui/dropdown-menu'
-import { Globe, Check } from 'lucide-react'
-
-const LANGUAGES = [
-  { code: 'en', label: 'English', flag: 'EN' },
-  { code: 'fr', label: 'Fran\u00e7ais', flag: 'FR' },
-] as const
-
-type LanguageCode = (typeof LANGUAGES)[number]['code']
-
-export function LanguageSwitcher() {
-  const locale = useLocale() as LanguageCode
-  const router = useRouter()
-  const [isPending, startTransition] = useTransition()
-
-  const currentLang = LANGUAGES.find((l) => l.code === locale) ?? LANGUAGES[0]
-
-  const switchLanguage = (code: LanguageCode) => {
-    // Set cookie with 1 year expiry
-    document.cookie = `locale=${code};path=/;max-age=${365 * 24 * 60 * 60};samesite=lax`
-    // Refresh to re-run server components with new locale
-    startTransition(() => {
-      router.refresh()
-    })
-  }
-
-  return (
-    <DropdownMenu>
-      <DropdownMenuTrigger asChild>
-        <Button variant="ghost" size="sm" className="gap-2" disabled={isPending}>
-          <Globe className="h-4 w-4" />
-          <span className="font-medium">{currentLang.flag}</span>
-        </Button>
-      </DropdownMenuTrigger>
-      <DropdownMenuContent align="end">
-        {LANGUAGES.map((lang) => (
-          <DropdownMenuItem
-            key={lang.code}
-            onClick={() => switchLanguage(lang.code)}
-            className="gap-2"
-          >
-            <span className="font-medium w-6">{lang.flag}</span>
-            <span>{lang.label}</span>
-            {locale === lang.code && <Check className="ml-auto h-4 w-4" />}
-          </DropdownMenuItem>
-        ))}
-      </DropdownMenuContent>
-    </DropdownMenu>
-  )
-}