feat: migrate to Next.js 15 App Router with i18n and multi-page SEO

- Replace Vite+React SPA with Next.js 15, TypeScript, App Router
- Static export (output: 'export'), deploy via npm run deploy
- i18n routing: /ru/... and /en/... with generateStaticParams
- New pages: /uslugi/ (catalog), /uslugi/[slug]/ (8 service pages), /faq/, /kontakty/
- SEO: generateMetadata on all pages, JSON-LD Service schema, hreflang alternates
- ContactForm: 'use client', Turnstile + POST to /api/contact.php
- Fonts: Manrope via next/font/google (CSS variable)
- Remove: vite.config.js, entry-server.jsx, prerender scripts, LanguageContext

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

src/components/layout/Header.tsx

@@ -0,0 +1,69 @@
+'use client'
+import { useState } from 'react'
+import Link from 'next/link'
+import Image from 'next/image'
+import { usePathname, useRouter } from 'next/navigation'
+import { Menu, X } from 'lucide-react'
+import { getDictionary, type Locale } from '@/lib/i18n'
+
+export default function Header({ lang }: { lang: string }) {
+  const [menuOpen, setMenuOpen] = useState(false)
+  const pathname = usePathname()
+  const router = useRouter()
+  const d = getDictionary(lang)
+
+  const links = [
+    { label: d.nav.services, href: `/${lang}/uslugi/` },
+    { label: d.nav.about, href: `/${lang}/#about` },
+    { label: d.nav.faq, href: `/${lang}/faq/` },
+  ]
+
+  function toggleLang() {
+    const newLang = lang === 'ru' ? 'en' : 'ru'
+    const newPath = pathname.replace(`/${lang}`, `/${newLang}`)
+    router.push(newPath)
+  }
+
+  return (
+    <header className="fixed top-0 left-0 right-0 z-50 bg-white shadow-sm">
+      <div className="max-w-6xl mx-auto px-4 sm:px-6 h-16 flex items-center justify-between">
+        <Link href={`/${lang}/`} className="flex items-center">
+          <Image src="/logo.png" alt="Сисадмингрупп" width={48} height={48} className="h-12 w-auto" />
+        </Link>
+        <nav className="hidden md:flex items-center gap-8">
+          {links.map(l => (
+            <Link key={l.href} href={l.href} className="text-sm font-medium text-slate-600 hover:text-blue-700 transition-colors">
+              {l.label}
+            </Link>
+          ))}
+          <button onClick={toggleLang} className="text-sm font-semibold text-slate-500 hover:text-blue-700 transition-colors border border-slate-200 rounded px-2 py-0.5">
+            {lang === 'ru' ? 'EN' : 'RU'}
+          </button>
+          <Link href={`/${lang}/kontakty/`} className="px-4 py-2 bg-blue-700 hover:bg-blue-800 text-white text-sm font-semibold rounded transition-colors">
+            {d.nav.contact}
+          </Link>
+        </nav>
+        <div className="md:hidden flex items-center gap-3">
+          <button onClick={toggleLang} className="text-sm font-semibold text-slate-500 border border-slate-200 rounded px-2 py-0.5">
+            {lang === 'ru' ? 'EN' : 'RU'}
+          </button>
+          <button onClick={() => setMenuOpen(!menuOpen)} className="p-1 text-slate-700">
+            {menuOpen ? <X size={22} /> : <Menu size={22} />}
+          </button>
+        </div>
+      </div>
+      {menuOpen && (
+        <div className="md:hidden bg-white border-t border-slate-100 px-4 py-4 flex flex-col gap-4">
+          {links.map(l => (
+            <Link key={l.href} href={l.href} onClick={() => setMenuOpen(false)} className="text-sm font-medium text-slate-700 hover:text-blue-700">
+              {l.label}
+            </Link>
+          ))}
+          <Link href={`/${lang}/kontakty/`} onClick={() => setMenuOpen(false)} className="text-sm font-medium text-blue-700">
+            {d.nav.contact}
+          </Link>
+        </div>
+      )}
+    </header>
+  )
+}