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/main.tsx

@@ -1,10 +1,13 @@
 import React from 'react'
 import ReactDOM from 'react-dom/client'
 import App from './App'
+import { ThemeProvider } from './context/ThemeContext'
 import './index.css'
 
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>
-    <App />
+    <ThemeProvider>
+      <App />
+    </ThemeProvider>
   </React.StrictMode>,
 )