Generate Random NFT

You are asked to randomly generate n unique Non-Fungible Tokens (NFTs). Each NFT must select exactly one value for every trait category provided. The traits are given as a JSON object where each key is a category (e.g. "background", "eyes", "nose") and the value is a list of possible strings for that category. Your generator must be deterministic: when the same seed and the same n are supplied, the exact same collection (same traits in the same order) must be returned. To achieve this, use a seeded pseudo-random number generator (PRNG) that you implement yourself; do not use language built-ins that you cannot seed. Return the collection as a list of JSON objects, each representing one NFT with its selected traits.