RAG Eval Lite — synthetic retrieval metrics starter

Minimal Python kit to run a toy RAG retrieval eval on synthetic docs/QA.

Includes precision@k / recall@k / hit@k. No API keys, no model weights, stdlib-first.

Try the free synthetic sample ($0): https://payhip.com/b/kdH7J

Need a compact reference? Field Card ($4.99): https://payhip.com/b/Lrw6Y