feat: bilingual website (DE/EN) with language switcher

Add LangContext with localStorage persistence (default: DE).
DE/EN toggle in Nav (top-right, before CTA button).

All pages translated:
- Home: all 8 sections incl. NIS2 block
- Features: all 13 sections with full German bullet points
- Drivers: headings and descriptions
- Getting Started (coming soon)
- Roadmap: bilingual data arrays inline (Planned + Under consideration)
- NIS2: full Art. 21 mapping, evidence blocks, coming-soon list

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

src/context/LangContext.tsx

@@ -0,0 +1,37 @@
+import { createContext, useContext, useState, useEffect, type ReactNode } from 'react'
+import { translations, type Lang } from '../i18n/translations'
+
+interface LangContextValue {
+  lang: Lang
+  setLang: (l: Lang) => void
+  t: typeof translations.en
+}
+
+const LangContext = createContext<LangContextValue | null>(null)
+
+export function LangProvider({ children }: { children: ReactNode }) {
+  const [lang, setLangState] = useState<Lang>(() => {
+    const stored = localStorage.getItem('lang')
+    return stored === 'de' || stored === 'en' ? stored : 'de'
+  })
+
+  useEffect(() => {
+    localStorage.setItem('lang', lang)
+  }, [lang])
+
+  function setLang(l: Lang) {
+    setLangState(l)
+  }
+
+  return (
+    <LangContext.Provider value={{ lang, setLang, t: translations[lang] }}>
+      {children}
+    </LangContext.Provider>
+  )
+}
+
+export function useLang() {
+  const ctx = useContext(LangContext)
+  if (!ctx) throw new Error('useLang must be used inside LangProvider')
+  return ctx
+}