feat(ui): SoC Refactoring & Config Validation

- Theme Context ausgelagert (ThemeContext.tsx + useDarkMode.ts)
- Config Validation mit TMDB-API-Key Pflicht (config_validation.py)
- Cache Key Centralization (cache/keys.py)
- CD-Ripping mit abcde implementiert (Worker)
- Docker Compose mit Healthchecks & LOG_LEVEL
- ROADMAP.md & SAVEPOINT.md aktualisiert

docker/ui/src/context/ThemeContext.tsx

@@ -0,0 +1,48 @@
+import { createContext, useContext, useEffect, useState, ReactNode } from 'react'
+
+type Theme = 'light' | 'dark'
+
+interface ThemeContextType {
+  theme: Theme
+  toggleTheme: () => void
+}
+
+const ThemeContext = createContext<ThemeContextType | undefined>(undefined)
+
+export function ThemeProvider({ children }: { children: ReactNode }) {
+  const [theme, setTheme] = useState<Theme>('light')
+
+  useEffect(() => {
+    const savedTheme = localStorage.getItem('theme')
+    const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches
+    
+    if (savedTheme === 'dark' || (!savedTheme && prefersDark)) {
+      setTheme('dark')
+      document.documentElement.setAttribute('data-theme', 'dark')
+    } else {
+      setTheme('light')
+      document.documentElement.setAttribute('data-theme', 'light')
+    }
+  }, [])
+
+  const toggleTheme = () => {
+    const newTheme = theme === 'dark' ? 'light' : 'dark'
+    setTheme(newTheme)
+    localStorage.setItem('theme', newTheme)
+    document.documentElement.setAttribute('data-theme', newTheme)
+  }
+
+  return (
+    <ThemeContext.Provider value={{ theme, toggleTheme }}>
+      {children}
+    </ThemeContext.Provider>
+  )
+}
+
+export function useDarkMode() {
+  const context = useContext(ThemeContext)
+  if (!context) {
+    throw new Error('useDarkMode must be used within a ThemeProvider')
+  }
+  return context
+}