refactor: mark dead exports with TODO, deduplicate field sanitization, fix import placement

src/lib/redis-cache.ts

@@ -33,9 +33,7 @@ export async function redisCache<T>(
 	return fresh;
 }
 
-/**
- * Invalidate a cached key. No-op if Redis is unavailable.
- */
+// TODO: Check of dit weg kan — niet geïmporteerd in de codebase
 export async function invalidateCache(key: string): Promise<void> {
 	if (!redis) return;
 	try {