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>

tailwind.config.ts

@@ -0,0 +1,25 @@
+import type { Config } from 'tailwindcss'
+
+const config: Config = {
+  content: ['./src/**/*.{ts,tsx}'],
+  theme: {
+    extend: {
+      fontFamily: {
+        sans: ['var(--font-manrope)', 'sans-serif'],
+      },
+      colors: {
+        brand: {
+          50:  '#eff6ff',
+          100: '#dbeafe',
+          500: '#3b82f6',
+          600: '#2563eb',
+          700: '#1d4ed8',
+          900: '#1e3a8a',
+        },
+      },
+    },
+  },
+  plugins: [],
+}
+
+export default config