fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

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

website/lib/LanguageContext.tsx

@@ -0,0 +1,70 @@
+'use client'
+
+import { createContext, useContext, useState, useEffect, ReactNode } from 'react'
+import { Language, DEFAULT_LANGUAGE, isRTL, t as translate } from './i18n'
+
+interface LanguageContextType {
+  language: Language
+  setLanguage: (lang: Language) => void
+  t: (key: string) => string
+  isRTL: boolean
+}
+
+const LanguageContext = createContext<LanguageContextType | undefined>(undefined)
+
+const STORAGE_KEY = 'breakpilot-language'
+
+export function LanguageProvider({ children }: { children: ReactNode }) {
+  const [language, setLanguageState] = useState<Language>(DEFAULT_LANGUAGE)
+  const [mounted, setMounted] = useState(false)
+
+  // Load language from localStorage on mount
+  useEffect(() => {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    if (stored && ['de', 'en', 'tr', 'ar', 'ru', 'uk', 'pl'].includes(stored)) {
+      setLanguageState(stored as Language)
+    }
+    setMounted(true)
+  }, [])
+
+  // Update document direction for RTL languages
+  useEffect(() => {
+    if (mounted) {
+      document.documentElement.dir = isRTL(language) ? 'rtl' : 'ltr'
+      document.documentElement.lang = language
+    }
+  }, [language, mounted])
+
+  const setLanguage = (lang: Language) => {
+    setLanguageState(lang)
+    localStorage.setItem(STORAGE_KEY, lang)
+  }
+
+  const t = (key: string) => translate(key, language)
+
+  const value: LanguageContextType = {
+    language,
+    setLanguage,
+    t,
+    isRTL: isRTL(language),
+  }
+
+  // Prevent hydration mismatch
+  if (!mounted) {
+    return (
+      <LanguageContext.Provider value={{ ...value, language: DEFAULT_LANGUAGE, isRTL: false }}>
+        {children}
+      </LanguageContext.Provider>
+    )
+  }
+
+  return <LanguageContext.Provider value={value}>{children}</LanguageContext.Provider>
+}
+
+export function useLanguage() {
+  const context = useContext(LanguageContext)
+  if (context === undefined) {
+    throw new Error('useLanguage must be used within a LanguageProvider')
+  }
+  return context
+}