feat: add pitch-deck service to core infrastructure

Migrated pitch-deck from breakpilot-pwa to breakpilot-core.
Container: bp-core-pitch-deck on port 3012.

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

pitch-deck/lib/hooks/useLanguage.ts

@@ -0,0 +1,39 @@
+'use client'
+
+import { createContext, useContext, useState, useCallback, ReactNode } from 'react'
+import { Language } from '../types'
+import React from 'react'
+
+interface LanguageContextType {
+  lang: Language
+  toggleLanguage: () => void
+  setLanguage: (lang: Language) => void
+}
+
+const LanguageContext = createContext<LanguageContextType>({
+  lang: 'de',
+  toggleLanguage: () => {},
+  setLanguage: () => {},
+})
+
+export function LanguageProvider({ children }: { children: ReactNode }) {
+  const [lang, setLang] = useState<Language>('de')
+
+  const toggleLanguage = useCallback(() => {
+    setLang(prev => prev === 'de' ? 'en' : 'de')
+  }, [])
+
+  const setLanguage = useCallback((newLang: Language) => {
+    setLang(newLang)
+  }, [])
+
+  return React.createElement(
+    LanguageContext.Provider,
+    { value: { lang, toggleLanguage, setLanguage } },
+    children
+  )
+}
+
+export function useLanguage() {
+  return useContext(LanguageContext)
+}